0001603756-21-000014 | 10-K | XBRL Viewer | Axonics Modulation Technologies INC

Intangible Asset - Narrative (Details) - USD ($)	12 Months Ended
Intangible Asset - Narrative (Details) - USD ($)	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2013
Goodwill and Intangible Assets Disclosure [Abstract]
Fair value of intangible assets				$ 1,000,000.0
Gross carrying amount on intangible assets	$ 1,000,000.0	$ 1,000,000.0
Accumulated amortization of intangible assets	800,000	700,000
Amortization of intangible assets	$ 100,000	$ 100,000	$ 100,000

Consolidated Balance Sheets - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019
Current assets
Cash and cash equivalents	$ 241,181	$ 171,082
Short-term investments	0	12,592
Accounts receivable, net of allowance for doubtful accounts of $465 and $75 at December 31, 2020 and 2019, respectively	18,270	7,879
Inventory, net	63,060	15,659
Prepaid expenses and other current assets	5,435	4,468
Total current assets	327,946	211,680
Property and equipment, net	6,328	3,047
Intangible asset, net	196	311
Other assets	7,736	4,784
Total assets	342,206	219,822
Current liabilities
Accounts payable	10,660	5,882
Accrued liabilities	6,684	2,174
Accrued compensation and benefits	5,948	3,375
Operating lease liability, current portion	1,280	602
Debt, net of unamortized debt issuance costs, current portion	21,110	0
Total current liabilities	45,682	12,033
Operating lease liability, net of current portion	9,154	4,450
Debt, net of unamortized debt issuance costs, net of current portion	0	20,336
Total liabilities	54,836	36,819
Stockholders’ Equity
Preferred stock, par value $0.0001 per share; 10,000,000 shares authorized, no shares issued and outstanding at December 31, 2020 and 2019	0	0
Common stock, par value $0.0001 per share, 50,000,000 shares authorized at December 31, 2020 and 2019; 39,931,030 and 34,110,995 shares issued and outstanding at December 31, 2020 and 2019, respectively	4	3
Additional paid-in capital	522,296	363,012
Accumulated deficit	(234,499)	(179,584)
Accumulated other comprehensive loss	(431)	(428)
Total stockholders’ equity	287,370	183,003
Total liabilities and stockholders’ equity	$ 342,206	$ 219,822

Consolidated Statements of Mezzanine Equity - 12 months ended Dec. 31, 2018 - USD ($) $ in Thousands	Total	Preferred Stock Series A Convertible Preferred Stock	Preferred Stock Series B-1 Convertible Preferred Stock	Preferred Stock Series B-2 Convertible Preferred Stock	Preferred Stock Series C Convertible Preferred Stock	Noncontrolling Interests
Balance at beginning of period (shares) at Dec. 31, 2017		719,500	1,925,302	2,213,794	1,898,213
Balance at beginning of period at Dec. 31, 2017	$ 93,293	$ 14,021	$ 13,757	$ 17,572	$ 16,877	$ 31,066
Increase (Decrease) in Temporary Equity [Roll Forward]
Issuance of preferred stock for cash, net of issuance costs (shares)					2,233,333
Issuance of preferred stock for cash, net of issuance costs	19,899				$ 19,899
Conversion of preferred stock to common stock (shares)		(719,500)	(1,925,302)	(2,213,794)	(4,131,546)
Conversion of preferred stock to common stock	(113,192)	$ (14,021)	$ (13,757)	$ (17,572)	$ (36,776)	(31,066)
Balance at end of period (shares) at Dec. 31, 2018		0	0	0	0
Balance at end of period at Dec. 31, 2018	$ 0	$ 0	$ 0	$ 0	$ 0	$ 0

- Definition

Carrying amount, attributable to parent and noncontrolling interests, of an entity's issued and outstanding stock which is not included within permanent equity. Temporary equity is a security with redemption features that are outside the control of the issuer, is not classified as an asset or liability in conformity with GAAP, and is not mandatorily redeemable. Includes any type of security that is redeemable at a fixed or determinable price or on a fixed or determinable date or dates, is redeemable at the option of the holder, or has conditions for redemption which are not solely within the control of the issuer. Includes stock with a put option held by an ESOP and stock redeemable by a holder only in the event of a change in control of the issuer.

+ References + Details

Stockholders' Equity - Restricted Stock Units Narrative (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Unrecognized compensation cost, period for recognition	4 years
Restricted Stock Units
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Unrecognized compensation cost	$ 1.2	$ 4.3
Unrecognized compensation cost, period for recognition	10 months 24 days	1 year 6 months

Consolidated Statements of Stockholders' Equity (Deficit) (Parenthetical) - Common Stock - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Initial Public Offering
Initial public offering / Follow-on offering - issuance, less closing costs (shares)			9,200,000
Stock issuance price (USD per share)			$ 15.00
Stock issuance - closing costs	$ 0	$ 0	$ 11,951
Follow-on Offering
Initial public offering / Follow-on offering - issuance, less closing costs (shares)	4,600,000	5,345,000
Stock issuance price (USD per share)	$ 32.50	$ 22.00
Stock issuance - closing costs	$ 9,013	$ 7,141	$ 0

Stockholders' Equity - Stock Option Activity (Details) - USD ($)
$ / shares in Units, $ in Thousands

12 Months Ended

Dec. 31, 2020

Dec. 31, 2019

Dec. 31, 2018

Number of Options

Outstanding at beginning of period (shares)

2,847,101

1,514,347

903,857

Options granted (shares)

5,000

1,671,044

668,380

Options exercised (shares)

(767,792)

(281,744)

(55,840)

Options forfeited (shares)

(129,066)

(56,546)

(2,050)

Outstanding at end of period (shares)

1,955,243

2,847,101

1,514,347

Options exercisable (shares)

906,457

Weighted-Average Exercise Price Per Share

Outstanding at beginning of period (USD per share)

$ 13.22

$ 2.22

$ 1.18

Options granted (USD per share)

29.03

21.28

3.55

Options exercised (USD per share)

5.05

1.79

1.47

Options forfeited (USD per share)

20.20

13.43

1.23

Outstanding at end of period (USD per share)

16.01

$ 13.22

$ 2.22

Options exercisable (USD per share)

$ 14.30

Share-based Compensation Arrangement by Share-based Payment Award, Options, Additional Disclosures [Abstract]

Options exercised intrinsic value

^[1]

$ 25,066

$ 7,386

$ 23

Options outstanding intrinsic value

^[2]

66,302

Options exercisable intrinsic value

^[2]

$ 32,287

[1]	Represents the total difference between the Company’s closing stock price at the time of exercise and the stock option exercise price, multiplied by the number of options exercised.
[2]	Represents the total difference between the Company’s closing stock price on the last trading day of 2020 and the stock option exercise price, multiplied by the number of in-the-money options as of December 31, 2020. The amount of intrinsic value will change based on the fair market value of the Company’s stock.

Stockholders' Equity

12 Months Ended

Dec. 31, 2020

Equity [Abstract]

Stockholders' Equity

Stockholders’ Equity

Preferred Stock

Prior to the IPO, the Company had outstanding 12,219,315 shares of convertible preferred stock. Upon closing of the Company’s IPO on October 31, 2018, all shares of outstanding convertible preferred stock were automatically converted to 15,813,297 shares of the Company’s common stock. As of December 31, 2020, the Company is authorized to issue 10,000,000 shares of preferred stock with a par value of $0.0001 per share.

Common Stock

The following summarizes the rights of holders of our common stock:

Voting

The holders of our common stock are entitled to one vote per share. The number of authorized shares of common stock may be increased or decreased (but not below the number of shares thereof then outstanding) by the affirmative vote of the holders of a majority of the voting power of our capital stock entitled to vote, irrespective of the provisions of Section 242(b)(2) of the DGCL.

Dividends

Subject to preferences that may be applicable to the holders of outstanding shares of preferred stock and subject to applicable law, dividends may be declared and paid on the holders of our common stock when and as determined by our board of directors out of assets legally available for dividends.

As a Delaware corporation, the Company will be subject to certain restrictions on dividends under the DGCL. Generally, a Delaware corporation may only pay dividends either out of “surplus” or out of the current or the immediately preceding year’s net profits. Surplus is defined as the excess, if any, at any given time, of the total assets of a corporation over its total liabilities and statutory capital. The value of a corporation’s assets can be measured in a number of ways and may not necessarily equal their book value.

Liquidation Rights

Upon our voluntary or involuntary liquidation, dissolution or winding up, after satisfaction of all our liabilities and the payment of any liquidation preference of any outstanding preferred stock, the holders of shares of common stock will be entitled to share in all of our assets legally remaining for distribution after payment of all debt and other liabilities, subject to preferences that may be applicable to the holders of outstanding shares of preferred stock.

Redemption Rights

There are no redemption or sinking fund provisions applicable to our common stock.

Preemptive Rights and Conversion Rights

There are no preemptive or conversion rights applicable to our common stock.

Stock-Based Compensation Expense

Stock-based compensation expense included in the Company’s consolidated statements of comprehensive loss is allocated as follows (in thousands):


	Years Ended December 31,
	2020		2019		2018
Research and development	$	3,457	$	1,725	$	197
General and administrative	5,852		3,950		361
Sales and marketing	5,786		3,045		48
	$	15,095	$	8,720	$	606

Stock Option Activity

2014 Stock Option Plan

In 2014, the Company established its 2014 Stock Option Plan (the 2014 Plan), which provides for the granting of stock options to employees, directors, and consultants of the Company. As of December 31, 2020 and 2019, a total of 3,131,624 and 3,156,295 shares have been reserved for issuance under the 2014 Plan, respectively. As of December 31, 2020 and 2019, there were no shares available for grant under the 2014 Plan. The 2018 Omnibus Incentive Plan was adopted upon our IPO and replaced the 2014 Stock Option Plan for future grants.

2018 Omnibus Incentive Plan

On October 18, 2018, the Company adopted the 2018 Omnibus Incentive Plan (the 2018 Plan), under which the Company may grant cash and equity incentive awards to eligible service providers in order to attract, motivate and retain the talent for which it competes. The 2018 Plan provides for awards based on shares of the Company’s common stock. Subject to adjustment by the Company’s board of directors, the total number of shares authorized to be awarded under the 2018 Plan may not exceed 4,562,317. As of December 31, 2020 and 2019, there were 1,678,326 and 1,965,500 shares available for grant under the 2018 Plan, respectively.

The Company had shares of common stock reserved for future issuance as follows at:


	December 31,
	2020	2019

Options outstanding under the 2014 Plan	501,598	1,126,140

Options and restricted stock-based awards outstanding under the 2018 Plan	2,477,929	2,560,232
Options and restricted stock-based awards remaining under the 2018 Plan for future issuance	1,678,326	1,965,500
	4,657,853	5,651,872

The fair value of each stock option is measured as of the date of grant, and compensation expense is recognized over the period during which the recipient renders the required services to the Company (typically the vesting period). Stock-based compensation expense recognized is based on the estimated number of stock options that are expected to ultimately become exercisable. Forfeitures are estimated at the time of the grant and revised in subsequent periods to reflect differences between the estimates and the number of shares that actually become exercisable.

The option awards issued under the 2014 and 2018 Plans were measured based on fair value. The Company’s fair value calculations were made using the Black-Scholes option pricing model with the following assumptions:


	Years Ended December 31,
	2020	2019	2018
Expected term (in years)	6.05	5.07 - 6.16	5.00 - 6.96
Stock volatility	72.01%	70.02% - 77.52%	68.04% - 77.03%
Risk-free interest rate	1.37%	1.42% - 2.56%	2.26% - 3.07%
Dividend rate	—	—	—

The Company used the simplified method of determining the expected term of stock options as the Company believes this represents the best estimate of the expected term of a new option. The expected stock price volatility assumption was determined by examining the historical volatilities for industry peers, as the Company did not have sufficient trading history for the Company’s common stock. The Company will continue to analyze the historical stock price volatility and expected term assumption as more historical data for the Company’s common stock becomes available. The risk-free interest rate assumption is based on the U.S. Treasury instruments, whose term was consistent with the expected term of the Company’s stock options. The expected dividend assumption is based on the Company’s history and expectation of dividend payouts. The assumptions regarding the expected term of the options and the expected volatility of the stock price are subjective, and these assumptions have a significant effect on the estimated fair value amounts. The weighted-average grant date fair value of options granted was $18.56, $13.79, and $3.62 for the years ended December 31, 2020, 2019, and 2018 respectively.

As of December 31, 2020 and 2019, there was $11.6 million and $19.5 million, respectively, of total unrecognized compensation cost related to unvested stock options that is expected to be recognized over a weighted-average period of approximately 2.4 years and 3.2 years, respectively.

The following table summarizes stock option activity under the 2014 and 2018 Plans (in thousands, except share and per share data):


	Number of Options	Weighted-Average Exercise Price Per Share		Aggregate Intrinsic Value



Outstanding at December 31, 2017	903,857	$	1.18
Options granted	668,380	3.55
Options exercised	(55,840)	1.47		$	23	(1)
Options forfeited	(2,050)	1.23
Outstanding at December 31, 2018	1,514,347	2.22
Options granted	1,671,044	21.28
Options exercised	(281,744)	1.79		$	7,386	(1)
Options forfeited	(56,546)	13.43
Outstanding at December 31, 2019	2,847,101	13.22
Options granted	5,000	29.03
Options exercised	(767,792)	5.05		$	25,066	(1)
Options forfeited	(129,066)	20.20
Outstanding at December 31, 2020	1,955,243	$	16.01	$	66,302	(2)
Options exercisable at December 31, 2020	906,457	$	14.30	$	32,287	(2)

_____________________________________________

(1) Represents the total difference between the Company’s closing stock price at the time of exercise and the stock option exercise price, multiplied by the number of options exercised.

(2) Represents the total difference between the Company’s closing stock price on the last trading day of 2020 and the stock option exercise price, multiplied by the number of in-the-money options as of December 31, 2020. The amount of intrinsic value will change based on the fair market value of the Company’s stock.

The weighted-average remaining contractual term of options outstanding and exercisable is 7.7 years and 7.6 years at December 31, 2020 and 2019, respectively.

Restricted Shares Awards Activity

As of December 31, 2020 and 2019, there was $22.6 million and $11.8 million, respectively, of total unrecognized compensation cost related to unvested restricted shares awards that is expected to be recognized over a weighted-average period of approximately 3.3 years and 3.3 years, respectively.

The following table summarizes restricted shares awards activity:


	Number of Restricted Shares Awards	Weighted-Average Fair Value Per Share at Grant Date
Outstanding at December 31, 2017	—	$	—
Restricted shares awards granted	50,000	14.48
Outstanding at December 31, 2018	50,000	14.48
Restricted shares awards granted	580,667	24.08
Restricted shares awards vested	(27,551)	18.80
Restricted shares awards forfeited	(16,950)	21.09
Outstanding at December 31, 2019	586,166	23.59
Restricted shares awards granted	502,500	37.68
Restricted shares awards vested	(174,890)	23.29
Restricted shares awards forfeited	(96,593)	28.83
Outstanding at December 31, 2020	817,183	$	31.70

Restricted Stock Units Activity

As of December 31, 2020 and 2019, there was $1.2 million and $4.3 million, respectively, of total unrecognized compensation cost related to unvested restricted stock units that is expected to be recognized over a weighted-average period of approximately 0.9 years and 1.5 years, respectively.

The following table summarizes restricted stock units activity:


	Number of Restricted Stock Units	Weighted-Average Fair Value Per Share at Grant Date
Outstanding at December 31, 2018	—	$	—
Restricted stock units granted	248,104	21.48
Outstanding at December 31, 2019	248,104	21.48
Restricted stock units granted	8,000	29.03
Restricted stock units vested	(46,336)	14.19
Restricted stock units forfeited	(2,667)	14.19
Outstanding at December 31, 2020	207,101	$	23.49

Stock Subscriptions Receivable

As of December 31, 2017 and throughout 2018, several members of management of the Company exercised stock options covering 1,685,597 shares of common stock, in exchange for promissory notes with a principal balance of $1.8 million. These promissory notes bore interest at a rate of 4.5% per annum and were due in full in 2020 to 2022. The promissory notes could have become due earlier if the shares of common stock received from the option exercises are sold, the employee terminates employment with the Company, or pursuant to other provisions specified in the notes. The notes were secured by the shares of common stock received from the option exercises. On October 4, 2018, the Company entered into agreements with each noteholder to terminate each of their respective promissory notes and to forgive all respective obligations for payment thereof in connection with the Company’s IPO. As a result, on October 4, 2018, the Company forgave all outstanding stock subscriptions receivable referenced above in the aggregate amount of $1.8 million plus accrued interest, which amount was recorded as compensation expense.

Stock Warrants

In February 2018, in connection with the Company’s entry into the Loan Agreement (as defined below), the Company issued warrants to Silicon Valley Bank and Life Science Loans II, LLC, its counterparty. Each warrant entitles the holder thereof to purchase up to 33,333 shares of the Series C Preferred Stock at an exercise price of $9.00 per share. Initially, each warrant was exercisable for 16,667 shares of Series C Preferred Stock. In connection with the Term Loan Amendment in October 2018, the Company drew on Tranche B and C, and an additional 16,666 shares became exercisable under each warrant. Each warrant will expire on February 6, 2028. In connection with the IPO, the Company’s outstanding warrants to purchase shares of Series C convertible Preferred Stock were automatically converted into warrants to purchase up to an aggregate of 80,000 shares of common stock at an exercise price of $7.50 per share.

In 2018 and prior to the IPO, warrants to purchase 66,666 shares of the Company’s Series C Preferred Stock were outstanding and are considered liabilities, the value of which was recorded in current liabilities and was adjusted to fair value at each reporting period with the change reflected in the statements of comprehensive loss. The fair value of the warrants in 2018 at grant date and prior to the IPO approximated $1.0 million using the Black-Scholes option pricing model with the following assumptions: expected life of 10 years, risk-free interest rate of 2.5% and stock volatility of 68.5%. The values of the warrants are accounted for as deferred loan costs and amortized to interest expense on an effective interest method. In connection with the Company’s IPO, the conversion of preferred stock into common stock, and the conversion of the warrants to purchase Series C preferred stock into warrants to purchase common stock, the warrant liability of $1.0 million was reclassified to additional paid-in-capital. The change in fair value of the warrants in 2018 prior to their conversion to permanent equity totaled $0.3 million, which is recorded in interest and other expense.

On July 16, 2019, the Company issued and sold 32,529 shares of its common stock to SVB Financial Group (SVB) in connection with the exercise by SVB of its right to purchase 40,000 shares of its common stock under that certain warrant, dated as of February 6, 2018. The exercise price per share was $7.50, and was paid by SVB via forfeiture of shares pursuant to a cashless exercise provision in the warrant.

On May 29, 2019, the Company issued and sold 31,071 shares of its common stock to Life Science Loans II, LLC (Life Science Loans) in connection with the exercise by Life Science Loans of its right to purchase 40,000 shares of its common stock under that certain warrant, dated as of February 6, 2018. The exercise price per share was $7.50, and was paid by Life Science Loans via forfeiture of shares pursuant to a cashless exercise provision in the warrant.

No warrants were outstanding at December 31, 2020.

Stockholders' Equity - Restricted Stock Units Activity (Details) - Restricted Stock Units - $ / shares	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019
Number of Restricted Stock Units
Outstanding at beginning of period (shares)	248,104	0
Granted (shares)	8,000	248,104
Vested (shares)	(46,336)
Forfeited (shares)	(2,667)
Outstanding at end of period (shares)	207,101	248,104
Weighted-Average Fair Value Per Share at Grant Date
Outstanding at beginning of period (USD per share)	$ 21.48	$ 0
Granted (USD per share)	29.03	21.48
Vested (USD per share)	14.19
Forfeited (USD per share)	14.19
Outstanding at end of period (USD per share)	$ 23.49	$ 21.48

Intangible Asset (Tables)

12 Months Ended

Dec. 31, 2020

Goodwill and Intangible Assets Disclosure [Abstract]

Schedule of Estimated Future Amortization Expense

The estimated future amortization expense as of December 31, 2020, is as follows (in thousands):


2021	$	115
2022	81
	$	196

Stockholders' Equity - Stock-based Compensation Expense (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based compensation expense	$ 15,095	$ 8,720	$ 606
Research and development
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based compensation expense	3,457	1,725	197
General and administrative
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based compensation expense	5,852	3,950	361
Sales and marketing
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based compensation expense	$ 5,786	$ 3,045	$ 48

Property and Equipment (Tables)

12 Months Ended

Dec. 31, 2020

Property, Plant and Equipment [Abstract]

Schedule of Property and Equipment, Net

Property and equipment, net consists of the following (in thousands) at:


	December 31,
	2020		2019
Research and development equipment	$	1,205	$	1,086
Computer hardware and software	2,286		1,418
Tools and molds	1,404		1,303
Leasehold improvements	3,759		1,500
Furniture and fixtures	1,360		624
Construction in progress	129		176
	10,143		6,107
Less: accumulated depreciation and amortization	(3,815)		(3,060)
	$	6,328	$	3,047

Stockholders' Equity - Restricted Shares Award Narrative (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Unrecognized compensation cost, period for recognition	4 years
Restricted Shares Awards
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Unrecognized compensation cost	$ 22.6	$ 11.8
Unrecognized compensation cost, period for recognition	3 years 3 months 18 days	3 years 3 months 18 days

Stockholders' Equity - Stock Warrants (Details) $ / shares in Units, $ in Thousands			10 Months Ended	12 Months Ended
	Jul. 16, 2019 $ / shares shares	May 29, 2019 $ / shares shares	Oct. 30, 2018 USD ($) shares	Dec. 31, 2020 USD ($) shares	Dec. 31, 2019 USD ($)	Dec. 31, 2018 USD ($)	Nov. 02, 2018 shares	Oct. 31, 2018 $ / shares shares	Feb. 28, 2018 $ / shares shares
Class of Warrant or Right [Line Items]
Fair value of warrants outstanding \| $			$ 1,000
Warrants term			10 years
Change in fair value of warrants \| $			$ 300	$ 0	$ 0	$ 254
Warrants
Class of Warrant or Right [Line Items]
Exercise price of warrants (USD per share) \| $ / shares	$ 7.50	$ 7.50
Warrants issued (shares)	32,529	31,071
Warrants exercised (shares)	40,000	40,000
Warrants outstanding (shares)				0
Common Stock
Class of Warrant or Right [Line Items]
Exercise price of warrants (USD per share) \| $ / shares								$ 7.50
Number of common stock warrants converted from preferred stock warrants (shares)							80,000	80,000
Series C Convertible Preferred Stock \| Liabilities
Class of Warrant or Right [Line Items]
Number of common stock warrants converted from preferred stock warrants (shares)			66,666
Risk Free Interest Rate
Class of Warrant or Right [Line Items]
Fair value measurement of warrants (as a percent)			0.025
Price Volatility
Class of Warrant or Right [Line Items]
Fair value measurement of warrants (as a percent)			0.685
Silicon Valley Bank Warrants \| Series C Convertible Preferred Stock
Class of Warrant or Right [Line Items]
Number of shares called by warrants issued and issuable (shares)									33,333
Exercise price of warrants (USD per share) \| $ / shares									$ 9.00
Number of common stock warrants converted from preferred stock warrants (shares)									16,667
Silicon Valley Bank Warrants \| Series C Convertible Preferred Stock \| Term Loan due 2021 - Tranche B & C
Class of Warrant or Right [Line Items]
Number of common stock warrants converted from preferred stock warrants (shares)								16,666
Life Science Loans II, LLC \| Series C Convertible Preferred Stock
Class of Warrant or Right [Line Items]
Number of shares called by warrants issued and issuable (shares)									33,333
Exercise price of warrants (USD per share) \| $ / shares									$ 9.00
Number of common stock warrants converted from preferred stock warrants (shares)									16,667
Life Science Loans II, LLC \| Series C Convertible Preferred Stock \| Term Loan due 2021 - Tranche B & C
Class of Warrant or Right [Line Items]
Number of common stock warrants converted from preferred stock warrants (shares)								16,666

Noncontrolling Interest - Narrative (Details) - Common Stock - shares			12 Months Ended
	Nov. 02, 2018	Oct. 31, 2018	Dec. 31, 2018
Noncontrolling Interest [Line Items]
Conversion of preferred stock to common stock (shares)	15,813,297	15,813,297	15,813,297
Axonics Europe S.A.S.
Noncontrolling Interest [Line Items]
Conversion of preferred stock to common stock (shares)			4,221,715

Stockholders' Equity - Common Stock Reserved for Future Issuance (Details) - shares	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Options and restricted stock-based awards outstanding (shares)	1,955,243	2,847,101	1,514,347	903,857
Common stock reserved for future issuance (shares)	4,657,853	5,651,872
2014 Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Options and restricted stock-based awards remaining for future issuance (shares)	0	0
2018 Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Options and restricted stock-based awards remaining for future issuance (shares)	1,678,326	1,965,500
Stock Option \| 2014 Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Options and restricted stock-based awards outstanding (shares)	501,598	1,126,140
Stock Option and Restricted Stock-Based Awards \| 2018 Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Options and restricted stock-based awards outstanding (shares)	2,477,929	2,560,232
Options and restricted stock-based awards remaining for future issuance (shares)	1,678,326	1,965,500

Related Party Transactions - Narrative (Details) $ in Millions	Oct. 04, 2018 USD ($)
Related Party Transactions [Abstract]
Stock subscriptions receivable forgiven	$ 1.8

Employee Benefit Plan	12 Months Ended
Employee Benefit Plan	Dec. 31, 2020
Retirement Benefits [Abstract]
Employee Benefit Plan	Employee Benefit PlanThe Company sponsors a defined contribution retirement savings plan under Section 401(k) of the Internal Revenue Code. This plan covers all employees who meet minimum age and service requirements, and allows participants to defer a portion of their annual compensation on a pre- or post-tax basis. Contributions to the plan by the Company may be made at the discretion of the board of directors. During the years ended December 31, 2020, 2019, and 2018, the Company contributions to the plan amounted to $1.6 million, $1.1 million, and $0.3 million, respectively.

- Definition

The entire disclosure for retirement benefits.

+ References

Reference 1: http://www.xbrl.org/2003/role/exampleRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 715
-SubTopic 20
-Section 55
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+ Details

Stockholders' Equity - Fair Value Assumptions (Details)	12 Months Ended
Stockholders' Equity - Fair Value Assumptions (Details)	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Share-based Compensation Arrangement by Share-based Payment Award, Fair Value Assumptions and Methodology [Abstract]
Expected term (in years)	6 years 18 days
Stock volatility, minimum (as a percent)	72.01%	70.02%	68.04%
Stock volatility, maximum (as a percent)	72.01%	77.52%	77.03%
Risk-free interest rate, minimum (as a percent)	1.37%	1.42%	2.26%
Risk-free interest rate, maximum (as a percent)	1.37%	2.56%	3.07%
Dividend rate (as a percent)	0.00%	0.00%	0.00%
Minimum
Share-based Compensation Arrangement by Share-based Payment Award, Fair Value Assumptions and Methodology [Abstract]
Expected term (in years)		5 years 25 days	5 years
Maximum
Share-based Compensation Arrangement by Share-based Payment Award, Fair Value Assumptions and Methodology [Abstract]
Expected term (in years)		6 years 1 month 28 days	6 years 11 months 15 days

Commitments and Contingencies

12 Months Ended

Dec. 31, 2020

Commitments and Contingencies Disclosure [Abstract]

Commitments and Contingencies

Operating Leases

In August 2014, the Company entered into a five-year operating lease for approximately 12,215 square feet of office space beginning on November 1, 2014, and expiring on October 31, 2019. In June 2019, the lease was amended to extend the expiration date to October 31, 2020 and in September 2020, the lease was amended to extend

the expiration date to July 31, 2022. Upon the execution of the amendments, which were deemed to be a lease modification, the Company reassessed the lease liability using the discount rate at the modification date and recorded ROU assets for the same amount. The Company also reassessed the lease classification and concluded that the lease continues to be an operating lease. Under the terms of the lease, the Company is responsible for taxes, insurance, and maintenance expense. The lease contains certain scheduled rent increases. Rent expense is recognized on a straight-line basis over the expected lease term.

In November 2017, the Company entered into a seven-year operating lease for approximately 25,548 square feet of office space beginning on August 1, 2018, and expiring on August 31, 2025. In June 2019, the lease was amended to extend the expiration date to October 31, 2027. Upon the execution of the amendment, which was deemed to be a lease modification, the Company reassessed the lease liability using the discount rate at the modification date and recorded ROU assets for the same amount. The Company also reassessed the lease classification and concluded that the lease continues to be an operating lease. Under the terms of the lease, the Company is responsible for taxes, insurance, and maintenance expense. The lease contains certain scheduled rent increases. Rent expense is recognized on a straight-line basis over the expected lease term. The Company has a renewal option to extend the term of the lease for a period of five years beyond the initial term. Under the terms of the lease, the base rent payable with respect to each renewal term will be equal to the prevailing market rental rent as of the commencement of the applicable renewal term. In the event of a default of certain of the Company’s obligations under the lease, the Company’s landlord would have the right to terminate the lease.

In June 2019, the Company entered into an eight-year operating lease for approximately 32,621 square feet of office space beginning on January 15, 2020 and expiring on January 31, 2028. The Company uses these premises as its new principal executive offices and for general office space. The Company intends to utilize its other currently-leased spaces through the lease expiration dates to conduct the training of its sales team and for manufacturing purposes. Under the terms of the lease, the Company is responsible for taxes, insurance, and maintenance expense. The lease contains certain scheduled rent increases. Rent expense is recognized on a straight-line basis over the expected lease term. The Company has a renewal option to extend the term of the lease for a period of five years beyond the initial term. Under the terms of the lease, the base rent payable with respect to each renewal term will be equal to the prevailing market rental rent as of the commencement of the applicable renewal term. In the event of a default of certain of the Company’s obligations under the lease, the Company’s landlord would have the right to terminate the lease.

In August 2020, the Company entered into a 38-month operating lease (the New Lease) for approximately 5,693 square feet of warehouse space beginning on October 15, 2020 and expiring on December 31, 2023 (the Initial Term). The Company uses these premises for general warehouse space.

During the years ended December 31, 2020, 2019, and 2018, ROU assets obtained in exchange for new operating lease liabilities were $3.8 million, $1.5 million, and $3.3 million, respectively. As of December 31, 2020 and 2019, the ROU asset has a balance of $7.1 million and $4.2 million, respectively. The operating lease ROU asset is included within the Company’s other non-current assets, and lease liabilities are included in current or noncurrent liabilities on the Company’s consolidated balance sheets. During the years ended December 31, 2020, 2019, and 2018, cash paid for amounts included in operating lease liabilities were $1.5 million, $0.9 million, and $0.5 million, respectively. Amortization of the ROU asset was $0.9 million, $0.4 million, and $0.2 million for the years ended December 31, 2020, 2019, and 2018, respectively. As of December 31, 2020 and 2019, the weighted-average remaining lease term for the Company’s operating leases were 6.6 years and 7.8 years, respectively. The weighted-average discount rate used to determine the present value of the Company’s operating leases’ future payments was 6.7% and 7.25%, respectively.

Total lease cost for the years ended December 31, 2020, 2019, and 2018 are as follows (in thousands):


	December 31,
	2020		2019		2018
Lease cost
Operating lease cost	$	1,991	$	1,031	$	518
Short-term lease cost	95		177		154
Variable lease cost	179		138		6
Total lease cost	$	2,265	$	1,346	$	678

Maturities of operating lease liabilities as of December 31, 2020, are as follows (in thousands):


2021	$	1,945
2022	1,905
2023	1,803
2024	1,776
2025	1,850
Thereafter	3,862
	13,141
Less: imputed interest	(2,707)
	10,434
Less: operating lease liability, current portion	(1,280)
Operating lease liability, net of current portion	$	9,154

License Agreement

In October 2013, the Company entered into the License Agreement, pursuant to which AMF licensed the Company certain patents and know-how (collectively, the AMF IP) relating to, in relevant part, an implantable pulse generator and related system components in development by AMF as of that date, in addition to any peripheral or auxiliary devices, including all components, that when assembled, comprise such device, excluding certain implantable pulse generators (collectively, the AMF Licensed Products). Under the License Agreement, for each calendar year beginning in 2018, the Company is obligated to pay AMF a royalty on an AMF Licensed Product-by-AMF Licensed Product basis if one of the following conditions applies: (i) one or more valid claims within any of the patents licensed to the Company by AMF covers such AMF Licensed Products or the manufacture of such AMF Licensed Products or (ii) for a period of 12 years from the first commercial sale anywhere in the world of such AMF Licensed Product, in each case. The foregoing royalty is calculated as the greater of (a) 4% of all net revenue derived from the AMF Licensed Products, and (b) the Minimum Royalty, payable quarterly. The Minimum Royalty will automatically increase each year after 2018, subject to a maximum amount of $200,000 per year. The Company generated net revenue of $111.5 million, $13.8 million, and $0.7 million during the years ended December 31, 2020, 2019, and 2018, respectively, and recorded related royalties of $4.4 million, $0.6 million, and $0.1 million during the years ended December 31, 2020, 2019, and 2018, respectively. Royalty expense is included in operating expenses in the consolidated statements of comprehensive loss. Accrued royalty of $1.4 million and $0.4 million as of December 31, 2020 and 2019, respectively, is included within accrued liabilities on the Company’s consolidated balance sheets.

Legal Matters

On November 4, 2019, Medtronic, Inc., Medtronic Puerto Rico Operations Co., Medtronic Logistics LLC and Medtronic USA, Inc. (collectively, the Medtronic Affiliates) filed an initial complaint against the Company in the United States District Court for the Central District of California, Case No. 8:19-cv-2115, and amended the complaint on November 26, 2019. The Company refers to this matter as the Medtronic Litigation. The complaint

asserts that the Company’s r-SNM System infringes U.S. Patent Nos. 8,036,756, 8,626,314, 9,463,324 and 9,821,112 held by the Medtronic Affiliates, and the amended complaint further includes the additional patents 8,738,148; 8,457,758; and 7,774,069 (collectively, the Medtronic Patents). The Medtronic Litigation requests customary remedies for patent infringement, including (i) a judgment that the Company has infringed and is infringing the Medtronic Patents, (ii) damages, including treble damages for willful infringement, (iii) a permanent injunction preventing the Company from infringing the Medtronic Patents, (iv) attorneys’ fees, and (v) costs and expenses. The Company believes the allegations are without merit and is vigorously defending itself against them. Given the early stage of the Medtronic Litigation, the Company is unable to predict the likelihood of success of the claims of the Medtronic Affiliates against the Company or to quantify any risk of loss. The Medtronic Litigation could last for an extended period of time and require the Company to dedicate significant financial resources and management resources to its defense. An adverse ruling against the Company could materially and adversely affect its business, financial position, results of operations or cash flows and could also result in reputational harm. Even if the Company is successful in defending against these claims, the Medtronic Litigation could result in significant costs, delays in future product developments, reputational harm or other collateral consequences.

On March 16, 2020, the Company filed seven petitions before the United States Patent and Trademark Office (USPTO) requesting inter partes review (IPR) to contest the validity of each of the Medtronic patents that Medtronic has alleged are being infringed by the Company. In September 2020, the USPTO decided that it will accept or “institute” the IPR process for six of the seven patents, finding that the Company had demonstrated a reasonable likelihood that at least one, if not all, of the claims of these six patents are invalid. The Company is currently in the IPR discovery process. The USPTO will usually render a decision on the validity of contested patents within twelve months of instituting the review. The Company filed a motion to stay the proceedings before the United States District Court for the Central District of California pending resolution of the IPR process. The Company’s motion was granted by the court on May 8, 2020.

In addition to the Medtronic Litigation, the Company is and may continue to be involved in claims, legal proceedings, and investigations arising out of its operations in the normal course of business.

Nature of Operations and Summary of Significant Accounting Policies (Policies)	12 Months Ended
	Dec. 31, 2020
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Principles of Consolidation	Principles of Consolidation The accompanying consolidated financial statements include the accounts of the Company, its wholly-owned subsidiaries, Axonics Europe, S.A.S., Axonics Modulation Technologies U.K. Limited and Axonics Modulation Technologies Australia Pty Ltd. Intercompany accounts and transactions have been eliminated in consolidation.
Basis of Presentation	Basis of Presentation The accompanying consolidated financial statements have been prepared in accordance with accounting principles generally accepted in the United States (GAAP). Certain prior year reported amounts have been reclassified to conform with the 2020 presentation. Stock Split and Charter Amendment In October 2018, the board of directors and certain stockholders of the Company approved an amendment to the Company’s Certificate of Incorporation to (i) increase the authorized shares of common stock from 17,500,000 to 20,500,000, (ii) effect a 1.2-for-1 forward stock split of the Company’s common stock and (iii) define a “Qualified IPO” to include a per share price equal to at least $12.00 (as adjusted for stock splits, combinations, stock dividends, recapitalizations and the like). All shares of common stock, stock options, and per share information presented in the consolidated financial statements have been adjusted to reflect the stock split on a retroactive basis for all periods presented. Any fractional shares that resulted from the stock split were rounded up to the nearest whole share. There was no change in the par value of the Company’s common stock. The ratios by which shares of preferred stock are convertible into shares of common stock have been adjusted to reflect the effects of the forward stock split. In November 2018, the board of directors and certain stockholders of the Company approved an amendment to the Company’s Certificate of Incorporation to increase the authorized shares of common stock from 20,500,000 to 50,000,000 and authorize 10,000,000 shares of preferred stock.
Use of Estimates	Use of Estimates The preparation of consolidated financial statements in conformity with GAAP requires the Company’s management to make estimates and judgments that affect the reported amounts of assets, liabilities, and expenses, and related disclosure of contingent assets and liabilities. The Company bases its estimates on historical experience and on various other assumptions that it believes to be reasonable under the circumstances. The results of this evaluation then form the basis for making judgments about the carrying values of assets and liabilities that are not readily apparent from other sources. Actual results may differ from these estimates under different assumptions or conditions, and such differences may be material to the consolidated financial statements.
Revenue Recognition	Revenue Recognition Revenue recognized during the years ended December 31, 2020, 2019, and 2018 relates entirely to the sale of our r-SNM System. The Company has revenue arrangements that consist of a single performance obligation. The Company recognizes revenue at the point in time when it transfers control of promised goods to its customers. Revenue is measured as the amount of consideration it expects to receive in exchange for transferring goods. The amount of revenue that is recognized is based on the transaction price, which represents the invoiced amount and includes estimates of variable consideration such as discounts, where applicable. The Company does not offer rights of return or price protection. The amount of variable consideration included in the transaction price may be constrained and is included only to the extent that it is probable that a significant reversal in the amount of the cumulative revenue recognized under the contract will not occur in a future period. Payment terms, typically less than three months, are offered to the Company’s customers and do not include a significant financing component. The Company extends credit to its customers based upon an evaluation of the customer’s financial condition and credit history and generally requires no collateral. The Company does not have any contract balances related to product sales. The Company also does not have significant contract acquisition costs related to product sales.
Shipping and Handling Costs	Shipping and handling costs incurred for the delivery of goods to customers are included in cost of goods sold. Amounts billed to customers for shipping and handling are included in net revenue.
Allowance for Doubtful Accounts	Allowance for Doubtful Accounts The Company makes estimates of the collectability of accounts receivable. Upon adoption of ASU 2016-13, the Company did not recognize an adjustment to the beginning balance of retained earnings as the impact from adoption was not material. The Company’s estimate of future losses is made by management based upon historical bad debts, customer receivable balances, age of customer receivable balances, customers’ financial conditions and reasonable forecasted economic trends. Despite the Company’s efforts to minimize credit risk exposure, clients could be adversely affected if future economic and industry trends, including those related to COVID-19, change in such a manner as to negatively impact their cash flows. The full effects of COVID-19 on the Company’s clients are highly uncertain and cannot be predicted. As a result, the Company’s future collection experience can differ significantly from historical collection trends. If the Company’s clients experience a negative impact on their cash flows, it could have a material adverse effect on the Company’s results of operations and financial condition.
Cash and Cash Equivalents	Cash and Cash Equivalents Cash equivalents consist of short-term, highly liquid investments purchased with an original maturity of three months or less. Financial instruments that potentially subject the Company to a concentration of credit risk consist of cash and cash equivalents. At times, the cash and cash equivalent balances may exceed federally insured limits. The Company does not believe that this results in any significant credit risk as the Company’s policy is to place its cash and cash equivalents in highly-rated financial institutions.
Fair Value of Financial Instruments	Fair Value of Financial Instruments Fair value is defined as the price that would be received to sell an asset or paid to transfer a liability in an orderly transaction between market participants at the measurement date. A three-level fair value hierarchy prioritizes the inputs used to measure fair value. The hierarchy requires entities to maximize the use of observable inputs and minimize the use of unobservable inputs. The three levels of inputs used to measure fair value are as follows: •Level 1: Inputs are unadjusted quoted prices in active markets for identical assets or liabilities. •Level 2: Inputs are quoted prices for similar assets and liabilities in active markets or quoted prices for identical or similar instruments in markets that are not active and model-derived valuations in which all significant inputs and significant value drivers are observable in active markets. •Level 3: Inputs are unobservable inputs based on the Company’s assumptions and valuation techniques used to measure assets and liabilities at fair value. The inputs require significant management judgment or estimation. The Company’s assessment of the significance of an input to the fair value measurement requires judgment, which may affect the valuation of fair value assets and liabilities and their placement within the fair value hierarchy levels. The carrying amounts reported in the consolidated financial statements approximate the fair value for cash and cash equivalents, accounts receivable, accounts payables, and accrued expenses, due to their short-term nature. The carrying amount of the Company’s term loan, which is described below, approximates fair value, considering the interest rates are based on the prime interest rate.
Investment Securities	Investment Securities The Company classifies its investment securities as available-for-sale. Those investments in debt securities with maturities less than 12 months at the date of purchase are considered short-term investments. Those investments in debt securities with maturities greater than 12 months at the date of purchase are considered long-term investments. The Company’s investment securities classified as available-for-sale are recorded at fair value based on the fair value hierarchy (Level 1 and Level 2 inputs in the fair value hierarchy), and consists primarily of commercial paper, corporate notes and U.S. government and agency securities. Unrealized gains or losses, deemed temporary in nature, are reported as other comprehensive income within the consolidated statement of comprehensive income (loss). There were no unrealized gains or losses during the years ended December 31, 2020, 2019, and 2018. A decline in the fair value of any security below cost that is deemed other than temporary results in a charge to net income (loss) and the corresponding establishment of a new cost basis for the security. Premiums (discounts) are amortized (accreted) over the life of the related security as an adjustment to yield using the straight-line interest method. Dividend and interest income are recognized when earned. Realized gains or losses are included in net income (loss) and are derived using the specific identification method for determining the cost of securities sold.
Foreign Currency Translation	Foreign Currency Translation The functional currencies of the Company’s subsidiaries are currencies other than the U.S. dollar. The Company translates assets and liabilities of the foreign subsidiaries into U.S. dollars at the exchange rate in effect on the balance sheet date. Costs and expenses of the subsidiaries are translated into U.S. dollars at the average exchange rate during the period. Gains or losses from these translation adjustments are reported as a separate component of stockholders’ equity in accumulated other comprehensive loss until there is a sale or complete or substantially complete liquidation of the Company’s investment in the foreign subsidiary at which time the gains or losses will be realized and included in net income (loss). As of December 31, 2020 and 2019, all foreign currency translation gains (losses) have been unrealized and included in accumulated other comprehensive loss. Accumulated other comprehensive loss consists entirely of losses or gains from translation of foreign subsidiaries at December 31, 2020 and 2019. Foreign currency transaction gains and losses are included in results of operations and have not been significant for the periods presented.
Inventory, Net	Inventory, Net Inventories are stated at the lower of cost or net realizable value, with cost computed on a first-in, first-out basis. The Company reduces the carrying value of inventories for items that are potentially excess, obsolete, or slow-moving based on changes in customer demand, technology developments, or other economic factors. The Company capitalizes inventory produced for commercial sale. The Company capitalizes manufacturing costs as inventory following both the receipt of regulatory approval from regulatory bodies and the Company’s intent to commercialize. Costs associated with developmental products prior to satisfying the Company’s inventory capitalization criteria are charged to research and development expense as incurred. Products that have been approved by certain regulatory authorities are also used in clinical programs to assess the safety and efficacy of the products for usage that have not been approved by the FDA or other regulatory authorities. The form of product utilized for both commercial and certain clinical programs is identical and, as a result, the inventory has an “alternative future use” as defined in authoritative guidance. Component materials and purchased products associated with clinical development programs are included in inventory and charged to research and development expense when the product enters the research and development process and no longer can be used for commercial purposes and, therefore, does not have an “alternative future use.” For products that are under development and have not yet been approved by regulatory authorities, purchased component materials are charged to research and development expense when the inventory ownership transfers to the Company. The Company analyzes inventory levels to identify inventory that may expire prior to sale, inventory that has a cost basis in excess of its net realizable value, or inventory in excess of expected sales requirements. Although the manufacturing of the r-SNM System is subject to strict quality control, certain batches or units of product may no longer meet quality specifications or may expire, which would require adjustments to the Company’s inventory values. The Company also applies judgment related to the results of quality tests that are performed throughout the production process, as well as the understanding of regulatory guidelines, to determine if it is probable that inventory will be saleable. These quality tests are performed throughout the pre- and post-production processes, and the Company continually gathers information regarding product quality for periods after the manufacturing date. The r-SNM System currently has a maximum estimated shelf life range of 12 to 36 months and, based on sales forecasts, the Company expects to realize the carrying value of the product inventory. In the future, reduced demand, quality issues, or excess supply beyond those anticipated by management may result in a material adjustment to inventory levels, which would be recorded as an increase to cost of sales. The determination of whether or not inventory costs will be realizable requires estimates by the Company’s management. A critical input in this determination is future expected inventory requirements based on internal sales forecasts. Management then compares these requirements to the expiry dates of inventory on hand. To the extent that inventory is expected to expire prior to being sold, management will write down the value of inventory.
Property and Equipment	Property and Equipment Property and equipment are stated at cost less accumulated depreciation. Depreciation is computed using the straight-line method over the estimated useful lives of the assets, generally between three and seven years. Leasehold improvements are amortized over the lesser of the life of the lease or the useful life of the improvements. Maintenance and repairs are charged to expense as incurred. When assets are retired or otherwise disposed of, the cost and accumulated depreciation are removed from the balance sheet and any resulting gain or loss is reflected in operations.
Intangible Asset	Intangible Asset The intangible asset represents exclusive rights to an additional field-of-use on the patent suite within the License Agreement with AMF. The additional field-of-use was provided in exchange for 50,000 shares of Series A preferred stock, the fair value of which was $1.0 million in 2013. The intangible asset was recorded at its fair value of $1.0 million at the date contributed. In connection with the IPO, such shares of Series A preferred stock were converted into common stock. Amortization of this asset is recorded over the shorter of the patent or legal life on a straight-line basis. The weighted-average amortization period is 8.71 years. The Company will review the intangible asset for impairment whenever an impairment indicator exists. There have been no intangible asset impairment charges to date.
Impairment of Long-Lived Assets	Impairment of Long-Lived Assets The Company reviews its long-lived assets for impairment whenever events or changes in circumstances indicate that the carrying amount of an asset may not be recoverable. Recoverability is measured by comparing the carrying amount to the future net cash flows that the assets are expected to generate. If said assets are considered to be impaired, the impairment that would be recognized is measured by the amount by which the carrying amount of the assets exceeds the projected discounted future net cash flows arising from the asset. There have been no such impairments of long-lived assets to date.
Leases	Leases In accordance with ASU No. 2016-02, “Leases (Topic 842)”, components of a lease should be split into three categories: lease components, non-lease components, and non-components. The fixed and in-substance fixed contract consideration (including any consideration related to non-components) must be allocated based on the respective relative fair values to the lease components and non-lease components. Entities may elect not to separate lease and non-lease components. Rather, entities would account for each lease component and related non-lease component together as a single lease component. The Company has elected to account for lease and non-lease components together as a single lease component for all underlying assets and allocate all of the contract consideration to the lease component only. Topic 842 allows for the use of judgment in determining whether the assumed lease term is for a major part of the remaining economic life of the underlying asset and whether the present value of lease payments represents substantially all of the fair value of the underlying asset. The Company applies the bright line thresholds referenced in Topic 842 to assist in evaluating leases for appropriate classification. The aforementioned bright lines are applied consistently to the Company’s entire portfolio of leases. Operating lease ROU asset and operating lease liabilities are recognized based on the present value of the future minimum lease payments over the lease term at commencement date. As the Company’s lease does not provide an implicit rate, the Company uses its incremental borrowing rate, which is the rate for a fully collateralized amortizing loan with the same maturity as the lease term, based on the information available at commencement date in determining the present value of future payments. The operating lease ROU asset also includes any lease payments made and excludes lease incentives and initial direct costs incurred. The lease terms may include options to extend or terminate the lease when it is reasonably certain that the Company will exercise that option. Lease expense for minimum lease payments is recognized on a straight-line basis over the lease term.
Research and Development	Research and Development Research and development costs are charged to operations as incurred. Research and development costs include salary and personnel-related costs, costs of clinical studies and testing, supplies and materials, and outside consultant costs.
Advertising Expense	Advertising ExpenseThe Company expenses advertising costs as they are incurred.
Income Taxes	Income Taxes The Company accounts for income taxes using the asset and liability method to compute the difference between the tax basis of assets and liabilities and the related financial amounts, using currently enacted tax rates. The Company has deferred tax assets. The realization of these deferred tax assets is dependent upon the Company’s ability to generate sufficient taxable income in future years. Valuation allowances are established, when necessary, to reduce deferred tax assets to the amount that more likely than not will be realized. The Company evaluates the recoverability of the deferred tax assets annually, and maintains a full valuation allowance on its deferred tax assets. The Company recognizes the tax benefit from an uncertain tax position only if it is more likely than not that the tax position will be sustained on examination by taxing authorities, based on the technical merits of the position. The Company is subject to transfer pricing and other tax regulations designed to ensure that appropriate levels of income are reported as earned by the Company’s U.S. and foreign entities and are taxed accordingly. In the normal course of business, the Company is audited by federal, state and foreign tax authorities, and subject to inquiries from those tax authorities regarding the amount of taxes due. These inquiries may relate to the timing and amount of deductions and the allocation of income among various tax jurisdictions. The Company’s policy is to recognize interest and penalties related to unrecognized tax benefits, if any, in income tax expense.
Stock-Based Compensation	Stock-Based Compensation The Company measures the cost of employee and non-employee services in exchange for an award of equity instruments based on the grant-date fair value of the award and recognizes compensation cost over the requisite service period (typically the vesting period), generally four years. Forfeitures are estimated at the time of the grant and revised in subsequent periods to reflect differences between the estimates and the number of shares that actually become exercisable. The Company uses the Black-Scholes option pricing model to determine the fair value of stock options (as of the date of grant) that have service conditions for vesting. Stock options and restricted shares awards vest based on service conditions, typically over four years. The Company also grants shares of performance-based restricted stock units that typically vest after one year only if the Company has also achieved certain performance objectives as defined and approved by the Company’s board of directors. The fair value of performance awards are determined based on the Company’s stock price at the date of grant and expensed over the performance period based on the probability of achieving the performance objectives. In addition, the Company also grants market-based restricted stock units that have combined market conditions and service conditions for vesting, for which the Company uses the Monte Carlo valuation model to value equity awards (as of the date of grant).
Net Loss per Share of Common Stock	Net Loss per Share of Common Stock Basic net loss per share of common stock is calculated by dividing the net loss attributable to common stockholders by the weighted-average number of shares of common stock outstanding during the period, without consideration for potentially dilutive securities. Diluted net loss per share is computed by dividing the net loss attributable to common stockholders by the weighted-average number of shares of common stock and potentially dilutive securities outstanding for the period. For purposes of the diluted net loss per share calculation, convertible preferred stock, common and preferred stock warrants, common stock options, unvested RSAs and RSUs are considered to be potentially dilutive securities. Because the Company has reported a net loss in all periods presented, diluted net loss per share of common stock is the same as basic net loss per share of common stock for those periods. For the years ended December 31, 2020, 2019, and 2018, there were 2,300,982, 1,737,430, and 9,192,127 potentially dilutive weighted-average shares, respectively, that were not included in the computation of diluted weighted-average shares of common stock and common stock equivalent shares outstanding because their effect would have been antidilutive given the Company’s net loss.
Recently Adopted Accounting Pronouncements and Recent Accounting Pronouncements	Recently Adopted Accounting Pronouncements In August 2018, the FASB issued ASU No. 2018-15, “Intangibles—Goodwill and Other—Internal-Use Software (Subtopic 350-40): Customer’s Accounting for Implementation Costs Incurred in a Cloud Computing Arrangement That Is a Service Contract,” which aligns the requirements for capitalizing implementation costs incurred in a hosting arrangement that is a service contract with the requirements for capitalizing implementation costs incurred to develop or obtain internal-use software (and hosting arrangements that include an internal-use software license). This guidance is effective for annual periods beginning after December 15, 2019, which was the Company’s first quarter of fiscal year 2020. The adoption of this guidance did not have an impact on the Company’s consolidated financial statements or related disclosures. In August 2018, the FASB issued ASU No. 2018-13, “Fair Value Measurement (Topic 820): Disclosure Framework—Changes to the Disclosure Requirements for Fair Value Measurement,” which modifies the disclosure requirements on fair value measurements and is intended to improve the effectiveness of disclosures, including the consideration of costs and benefits. This guidance is effective for annual periods beginning after December 15, 2019, which was the Company’s first quarter of fiscal year 2020, with early adoption permitted. The adoption of this guidance did not have an impact on the Company’s consolidated financial statements or related disclosures. In June 2016, the FASB issued ASU No. 2016-13, “Financial Instruments—Credit Losses (Topic 326): Measurement of Credit Losses on Financial Instruments,” which updates the methodology used to measure current expected credit losses (CECL). This guidance applies to financial assets measured at amortized cost, including loans, held-to-maturity debt securities, net investments in leases, and trade accounts receivable as well as certain off-balance sheet credit exposures, such as loan commitments. This guidance replaces the current incurred loss impairment methodology with a methodology to reflect CECL and requires consideration of a broader range of reasonable and supportable information to explain credit loss estimates. The guidance must be adopted using a modified retrospective transition method through a cumulative-effect adjustment to retained earnings (deficit) in the period of adoption. This guidance is effective for the Company as of January 1, 2020. The adoption of this guidance did not have an impact on the Company’s consolidated financial statements or related disclosures Recent Accounting Pronouncements In December 2019, the FASB issued ASU 2019-12, “Income Taxes—Simplifying the Accounting for Income Taxes,” which simplifies the accounting for income taxes by clarifying and amending existing guidance related to the recognition of franchise tax, the evaluation of a step-up in the tax basis of goodwill and the effects of enacted changes in tax laws or rates in the effective tax rate computation, among other clarifications. This guidance is effective for annual periods beginning after December 15, 2020, which is the Company’s first quarter of fiscal year 2021, with early adoption permitted. The adoption of this guidance is not expected to have an impact on the Company’s consolidated financial statements or related disclosures.

Long-Term Debt

12 Months Ended

Dec. 31, 2020

Debt Disclosure [Abstract]

Long-Term Debt

In February 2018, the Company entered into the Loan and Security Agreement (the Loan Agreement), with Silicon Valley Bank, providing for a term loan (the Term Loan). Pursuant to the Loan Agreement, the Company may request up to $20.0 million in three tranches of term loans with such drawn obligations maturing on June 1, 2021. The Company requested $10.0 million from the first tranche, simultaneously with the entry into the Loan Agreement, which is currently outstanding. The Company may request (a) an additional $5.0 million (Tranche B), after the date commencing on the later of (i) the date that the Company achieves positive three-month results in the Company’s ARTISAN-SNM pivotal study, as confirmed to Silicon Valley Bank by a member of the Company’s management team and a member of its board of directors, and (ii) July 1, 2018, and ending on December 31, 2018 and (b) another $5.0 million (Tranche C), after the date commencing on the later of (i) the date that Silicon Valley Bank receives evidence, in form and substance reasonably satisfactory to Silicon Valley Bank, that the Company has received its pre-market approval (PMA) in the United States for its r-SNM System or gross proceeds from the sale of its equity securities of not less than $20.0 million, and (ii) January 1, 2019, and ending on March 31, 2019, subject to certain terms and conditions. If either Tranche B or Tranche C is drawn, then the maturity of the Term Loan is automatically extended to December 1, 2021.

The Loan Agreement provides for monthly interest payments through December 31, 2018; provided that, (i) if the Company requests and Silicon Valley Bank funds Tranche B or Tranche C, this interest-only period automatically extends through June 30, 2019, and (ii) if the Company has received a PMA in the United States for its r-SNM System and the Company requests and Silicon Valley Bank funds Tranche C, the interest-only period automatically extends through December 31, 2019. On the first day of the end of the interest-only period, the Company will be required to repay the Term Loan in equal monthly installments of principal plus interest through maturity. Outstanding principal balances under the Term Loan bear interest at the prime rate plus 1.75%.

In October 2018, the Company and Silicon Valley Bank entered into an amendment to the Loan Agreement (the Loan Amendment) in connection with which the Company requested the full $5.0 million from Tranche B and the full $5.0 million from Tranche C. The Company received the $10.0 million from both tranches in October 2018. Pursuant to the Loan Amendment, Silicon Valley Bank agreed to (i) extend the interest only period from June 30, 2019 to December 31, 2019, without requiring the receipt of the Company’s PMA in the United States for the r-SNM System, and (ii) make Tranche C available immediately instead of January 1, 2019. In addition, as a result of the Company’s request of the full $5.0 million from Tranche B and the full $5.0 million from Tranche C, the maturity of the Term Loan has been automatically extended to December 1, 2021. The transaction was accounted for as a debt modification. See Note 6 for discussion regarding stock warrants granted in connection with the Term Loan.

In December 2019, the Company and Silicon Valley Bank entered into a second amendment to the Loan Agreement (the Second Amendment). Pursuant to the Second Amendment, Silicon Valley Bank agreed to extend the interest only period from December 31, 2019 to December 31, 2020. In connection with the Second Amendment, the Company paid Silicon Valley Bank a non-refundable fee of $0.2 million. The transaction was accounted for as a debt modification.

The Company may prepay amounts outstanding under the Term Loan in increments of $5.0 million at any time with 30 days prior written notice to Silicon Valley Bank. However, all prepayments of the Term Loan prior to maturity, whether voluntary or mandatory (acceleration or otherwise), are also subject to the payment of a prepayment fee equal to (i) for a prepayment made on or after the closing date through and including the first anniversary of the closing date, 3.00% of the principal amount of the Term Loan being prepaid, (ii) for a prepayment made after the date which is the first anniversary of the closing date through and including the second anniversary of the closing date, 2.00% of the principal amount of the Term Loan being prepaid, and (iii) for a prepayment made after the date which is the second anniversary of the closing date and before the maturity date, 1.00% of the principal amount of the Term Loan being prepaid. Additionally, on the earliest to occur of (i) the maturity date of the Term Loan, (ii) the acceleration of the Term Loan, or (iii) the prepayment of the Term Loan, the Company will be required to make a final payment equal to the original principal amount of such tranche multiplied by 7.50%. The Company accrued the portion of the final payment calculated based on the amount outstanding under the Term Loan.

All obligations under the Term Loan are secured by a first priority lien on substantially all of the Company’s assets, excluding intellectual property assets and more than 65% of the shares of voting capital stock of any of its foreign subsidiaries. The Company has agreed with Silicon Valley Bank not to encumber its intellectual property assets without Silicon Valley Bank’s prior written consent unless a security interest in the underlying intellectual property is necessary to have a security interest in the accounts and proceeds that are part of the assets securing the Term Loan, in which case the Company’s intellectual property shall automatically be included within the assets securing the Term Loan. As of December 31, 2020, the Company was in compliance with all debt covenant requirements under the Term Loan.

Debt, net of unamortized debt issuance costs, consists of the following (in thousands) at:


	December 31,
	2020		2019
Debt, principal	$	20,000	$	20,000
Accrued loan fees	1,500		1,500
Debt, total	21,500		21,500
Less: unamortized debt issuance costs	(390)		(1,164)
Debt, net of unamortized debt issuance costs	$	21,110	$	20,336

Expected future principal payments for the term loan as of December 31, 2020, are as follows (in thousands):


2021	$	21,500

	$	21,500

All obligations under the Term Loan, including accrued interest, prepayment fees, and the minimum final payment, consisting of a 7.5% premium principal amount, were repaid in full in January 2021 (see Note 11).

Subsequent Events

Pay-off of Loan Agreement Maturing December 2021

In January 2021, the principal amount, accrued interest, accrued loan fees, and prepayment fees related to the Term Loan were paid in full. The unamortized debt issuance costs of $0.4 million as of December 31, 2020 will be expensed and recognized as interest expense during the three months ending March 31, 2021.

Acquisition of Contura Limited

In February 2021, the Company acquired London-based Contura Limited (Contura) and its flagship product, Bulkamid, for total consideration of $200 million in cash and stock, and a potential future milestone payment of $35 million. Total upfront consideration is comprised of approximately $141.3 million paid in cash and the issuance of 1,096,583 shares of stock. The Company also entered into a manufacturing agreement for the supply of the Bulkamid hydrogel. The Company has rights to a technology transfer after June 30, 2022 that would enable the Company to insource the manufacturing of Bulkamid. The initial accounting for the business combination, including the estimated fair value of assets and liabilities acquired, is incomplete as a result of the timing of the acquisition.

Loan and Security Agreement with Silicon Valley Bank

In February 2021, the Company entered into a $75 million term loan with Silicon Valley Bank (the Loan) maturing February 2024. The Loan provides for monthly interest payments through August 2022, and monthly principal and interest payments from September 2022 through maturity. Outstanding principal balances under the Loan bear interest at the greater of (i) prime rate plus 5.75% or (ii) 9.00%. The Company will be required to make a final payment equal to the original principal amount multiplied by 6.00%.

Stockholders' Equity - Stock Subscriptions Receivable (Details) - USD ($) $ in Thousands		12 Months Ended
	Oct. 04, 2018	Dec. 31, 2018
Equity [Abstract]
Exercised stock options in exchange for promissory notes (shares)	1,685,597
Stock subscriptions receivable	$ 1,800
Promissory notes interest rate (as a percent)	4.50%
Loan forgiveness of stock subscription receivable	$ 1,800	$ 1,824

Commitments and Contingencies - Future Minimum Lease Payments for Operating Lease (Details) - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019
Lessee, Operating Lease, Liability, Payment, Due [Abstract]
2021	$ 1,945
2022	1,905
2023	1,803
2024	1,776
2025	1,850
Thereafter	3,862
Total lease payments	13,141
Less: imputed interest	(2,707)
Operating lease liability	10,434
Less: operating lease liability, current portion	(1,280)	$ (602)
Operating lease liability, net of current portion	$ 9,154	$ 4,450

Property and Equipment - Narrative (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Property, Plant and Equipment [Line Items]
Depreciation and amortization expense	$ 1,741	$ 1,191	$ 946
Property and Equipment
Property, Plant and Equipment [Line Items]
Depreciation and amortization expense	$ 1,600	$ 1,100	$ 800

Long-Term Debt - Debt, Net of Unamortized Costs (Details) - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019
Debt Disclosure [Abstract]
Debt, principal	$ 20,000	$ 20,000
Accrued loan fees	1,500	1,500
Debt, total	21,500	21,500
Less: unamortized debt issuance costs	(390)	(1,164)
Debt, net of unamortized debt issuance costs	$ 21,110	$ 20,336

Cover Page - USD ($) $ in Millions	12 Months Ended
Cover Page - USD ($) $ in Millions	Dec. 31, 2020	Feb. 25, 2021	Jun. 30, 2020
Cover [Abstract]
Amendment Flag	false
Document Fiscal Year Focus	2020
Document Fiscal Period Focus	FY
Entity Central Index Key	0001603756
Current Fiscal Year End Date	--12-31
Document Type	10-K
Document Annual Report	true
Document Period End Date	Dec. 31, 2020
Document Transition Report	false
Entity File Number	001-38721
Entity Registrant Name	Axonics Modulation Technologies, Inc.
Entity Incorporation, State or Country Code	DE
Entity Tax Identification Number	45-4744083
Entity Address, Address Line One	26 Technology Drive
Entity Address, City or Town	Irvine,
Entity Address, State or Province	CA
Entity Address, Postal Zip Code	92618
City Area Code	(949)
Local Phone Number	396-6322
Title of 12(b) Security	Common stock, par value $0.0001 per share
Trading Symbol	AXNX
Security Exchange Name	NASDAQ
Entity Well-known Seasoned Issuer	Yes
Entity Voluntary Filers	No
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Entity Filer Category	Large Accelerated Filer
Entity Small Business	false
Entity Emerging Growth Company	false
ICFR Auditor Attestation Flag	true
Entity Shell Company	false
Entity Public Float			$ 1,135.8
Entity Common Stock, Shares Outstanding		41,523,375

Nature of Operations and Summary of Significant Accounting Policies - Changes in Allowance for Doubtful Accounts (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Accounts Receivable, Allowance for Credit Loss [Roll Forward]
Balance at beginning of period	$ 75	$ 0	$ 0
Bad debt expense	390	75	0
Balance at end of period	$ 465	$ 75	$ 0

Subsequent Events	12 Months Ended
Subsequent Events	Dec. 31, 2020
Subsequent Events [Abstract]
Subsequent Events	Subsequent Events Pay-off of Loan Agreement Maturing December 2021 In January 2021, the principal amount, accrued interest, accrued loan fees, and prepayment fees related to the Term Loan were paid in full. The unamortized debt issuance costs of $0.4 million as of December 31, 2020 will be expensed and recognized as interest expense during the three months ending March 31, 2021. Acquisition of Contura Limited In February 2021, the Company acquired London-based Contura Limited (Contura) and its flagship product, Bulkamid, for total consideration of $200 million in cash and stock, and a potential future milestone payment of $35 million. Total upfront consideration is comprised of approximately $141.3 million paid in cash and the issuance of 1,096,583 shares of stock. The Company also entered into a manufacturing agreement for the supply of the Bulkamid hydrogel. The Company has rights to a technology transfer after June 30, 2022 that would enable the Company to insource the manufacturing of Bulkamid. The initial accounting for the business combination, including the estimated fair value of assets and liabilities acquired, is incomplete as a result of the timing of the acquisition. Loan and Security Agreement with Silicon Valley Bank In February 2021, the Company entered into a $75 million term loan with Silicon Valley Bank (the Loan) maturing February 2024. The Loan provides for monthly interest payments through August 2022, and monthly principal and interest payments from September 2022 through maturity. Outstanding principal balances under the Loan bear interest at the greater of (i) prime rate plus 5.75% or (ii) 9.00%. The Company will be required to make a final payment equal to the original principal amount multiplied by 6.00%.

Consolidated Balance Sheets - (Parenthetical) - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019
Statement of Financial Position [Abstract]
Allowance for doubtful accounts	$ 465	$ 75
Preferred stock, par value (USD per share)	$ 0.0001	$ 0.0001
Preferred stock authorized (shares)	10,000,000	10,000,000
Preferred stock issued (shares)	0	0
Preferred stock outstanding (shares)	0	0
Common stock, par value (USD per share)	$ 0.0001	$ 0.0001
Common stock authorized (shares)	50,000,000	50,000,000
Common stock issued (shares)	39,931,030	34,110,995
Common stock outstanding (shares)	39,931,030	34,110,995

Consolidated Statements of Stockholders' Equity (Deficit) - USD ($) $ in Thousands	Total	Common Stock	Additional Paid-in Capital	Stock Subscriptions Receivable	Accumulated Deficit	Accumulated Other Comprehensive Loss	Initial Public Offering	Initial Public Offering Common Stock	Initial Public Offering Additional Paid-in Capital	Follow-on Offering	Follow-on Offering Common Stock	Follow-on Offering Additional Paid-in Capital
Balance at beginning of period (shares) at Dec. 31, 2017		2,776,583
Balance at beginning of period at Dec. 31, 2017	$ (66,421)	$ 0	$ 2,900	$ (1,753)	$ (67,166)	$ (402)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Issuance of common stock for employee stock option exercises for promissory notes (shares)		48,720
Issuance of common stock for employee stock option exercises for promissory notes	0		71	(71)
Issuance of common stock for employee stock option exercises for cash (shares)		7,120
Issuance of common stock for employee stock option exercises for cash	9		9
Warrants for common stock	986		986
Repurchase of common stock (shares)		(38,786)
Repurchase of common stock	(473)		(473)
Forgiveness of stock subscriptions receivable	1,824			1,824
Conversion of preferred stock to common stock (shares)		15,813,297
Conversion of preferred stock to common stock	113,192	$ 2	113,190
Restricted Shares Award (RSA) issuances and forfeitures for terminations, net and stock-based compensation	606		606
Initial public offering / Follow-on offering - issuance, less closing costs (shares)								9,200,000
Initial public offering / Follow-on offering - issuance, less closing costs							$ 126,049	$ 1	$ 126,048
Foreign currency translation adjustment	(14)					(14)
Net loss	(32,483)				(32,483)
Balance at end of period (shares) at Dec. 31, 2018		27,806,934
Balance at end of period at Dec. 31, 2018	143,275	$ 3	243,337	0	(99,649)	(416)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Issuance of common stock for employee stock option exercises for cash (shares)		281,744
Issuance of common stock for employee stock option exercises for cash	506		506
Restricted Shares Award (RSA) issuances and forfeitures for terminations, net and stock-based compensation (shares)		613,717
Restricted Shares Award (RSA) issuances and forfeitures for terminations, net and stock-based compensation	7,655		7,655
Issuance of common stock for vesting of Restricted Stock Units (RSU) and stock-based compensation	1,065		1,065
Initial public offering / Follow-on offering - issuance, less closing costs (shares)											5,345,000
Initial public offering / Follow-on offering - issuance, less closing costs										$ 110,449		$ 110,449
Issuance of common stock for warrant exercise (shares)		63,600
Foreign currency translation adjustment	(12)					(12)
Net loss	$ (79,935)				(79,935)
Balance at end of period (shares) at Dec. 31, 2019	34,110,995	34,110,995
Balance at end of period at Dec. 31, 2019	$ 183,003	$ 3	363,012	0	(179,584)	(428)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Issuance of common stock for employee stock option exercises for cash (shares)		767,792
Issuance of common stock for employee stock option exercises for cash	3,703		3,703
Restricted Shares Award (RSA) issuances and forfeitures for terminations, net and stock-based compensation (shares)		405,907
Restricted Shares Award (RSA) issuances and forfeitures for terminations, net and stock-based compensation	11,792		11,792
Issuance of common stock for vesting of Restricted Stock Units (RSU) and stock-based compensation (shares)		46,336
Issuance of common stock for vesting of Restricted Stock Units (RSU) and stock-based compensation	3,303		3,303
Initial public offering / Follow-on offering - issuance, less closing costs (shares)											4,600,000
Initial public offering / Follow-on offering - issuance, less closing costs										$ 140,487	$ 1	$ 140,486
Foreign currency translation adjustment	(3)					(3)
Net loss	$ (54,915)				(54,915)
Balance at end of period (shares) at Dec. 31, 2020	39,931,030	39,931,030
Balance at end of period at Dec. 31, 2020	$ 287,370	$ 4	$ 522,296	$ 0	$ (234,499)	$ (431)

Commitments and Contingencies - Total Lease Cost (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Commitments and Contingencies Disclosure [Abstract]
Operating lease cost	$ 1,991	$ 1,031	$ 518
Short-term lease cost	95	177	154
Variable lease cost	179	138	6
Total lease cost	$ 2,265	$ 1,346	$ 678

Commitments and Contingencies (Tables)

12 Months Ended

Dec. 31, 2020

Commitments and Contingencies Disclosure [Abstract]

Schedule of Total Lease Cost

Total lease cost for the years ended December 31, 2020, 2019, and 2018 are as follows (in thousands):


	December 31,
	2020		2019		2018
Lease cost
Operating lease cost	$	1,991	$	1,031	$	518
Short-term lease cost	95		177		154
Variable lease cost	179		138		6
Total lease cost	$	2,265	$	1,346	$	678

Schedule of Maturities of Lease Liabilities

Maturities of operating lease liabilities as of December 31, 2020, are as follows (in thousands):


2021	$	1,945
2022	1,905
2023	1,803
2024	1,776
2025	1,850
Thereafter	3,862
	13,141
Less: imputed interest	(2,707)
	10,434
Less: operating lease liability, current portion	(1,280)
Operating lease liability, net of current portion	$	9,154

Property and Equipment - Summary (Details) - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019
Property, Plant and Equipment [Line Items]
Property and equipment, gross	$ 10,143	$ 6,107
Less: accumulated depreciation and amortization	(3,815)	(3,060)
Property and equipment, net	6,328	3,047
Research and development equipment
Property, Plant and Equipment [Line Items]
Property and equipment, gross	1,205	1,086
Computer hardware and software
Property, Plant and Equipment [Line Items]
Property and equipment, gross	2,286	1,418
Tools and molds
Property, Plant and Equipment [Line Items]
Property and equipment, gross	1,404	1,303
Leasehold improvements
Property, Plant and Equipment [Line Items]
Property and equipment, gross	3,759	1,500
Furniture and fixtures
Property, Plant and Equipment [Line Items]
Property and equipment, gross	1,360	624
Construction in progress
Property, Plant and Equipment [Line Items]
Property and equipment, gross	$ 129	$ 176

Income Taxes

12 Months Ended

Dec. 31, 2020

Income Tax Disclosure [Abstract]

Income Taxes

Income TaxesThe Company’s effective tax rate of approximately 0% differs from the federal statutory tax rate due primarily to providing a full valuation allowance on deferred tax assets.

Deferred income taxes reflect the net tax effects of temporary differences between the carrying amounts of assets and liabilities for financial reporting purposes and the amounts used for income tax purposes. Significant components of the Company’s net deferred tax assets are as follows (in thousands) as of:


	December 31,
	2020		2019
Compensation accruals	$	592	$	404
Depreciation and amortization	145		48
Lease liability	901		252
Net operating loss carryforwards	59,176		41,564

Other	4,438		3,752
Total deferred tax assets	65,252		46,020
Less: valuation allowance	(65,252)		(46,020)
Total net deferred tax assets	$	—	$	—

At December 31, 2020, the Company had federal and California net operating loss (NOL) carryforwards of approximately $213.5 million. Pursuant to Sections 382 and 383 of the Internal Revenue Code of 1986, as amended (the Internal Revenue Code), use of the Company’s NOL carryforwards may be limited if the Company experiences a cumulative change in ownership of greater than 50% in a rolling three-year period. The Company performed an analysis of changes in ownership for purposes of these Internal Revenue Code sections. Based on the study performed in 2020, the Company determined that an ownership change occurred in 2014, 2018 and 2019. The total reduction to the net operating loss carryforwards and R&D credit was $12.2 million and $1.5 million, respectively. The total reduction of the net operating loss carryforwards was offset by valuation allowance, and there was no impact to tax expense related to the limitation. Future ownership changes could impact the Company’s ability to utilize NOL carryforwards. The Company has recorded a full valuation allowance against its otherwise recognizable deferred income tax assets as of December 31, 2020 and 2019. The Company has determined, after evaluating all positive and negative historical and prospective evidence, that it is more likely than not that the deferred income tax assets will not be realized. The valuation allowance increased by $19.2 million for the year ended December 31, 2020, from $46.0 million to $65.3 million. During fiscal year 2020, we corrected the prior year balance of deferred tax assets relating to tax loss carryforwards as well as the valuation allowance related to those assets by an equal and offsetting amount. As a result, the tax loss carryforwards and valuation allowance previously reported as of December 31, 2019 have both been decreased in the table above by $3.9 million and corresponding revisions have been made to the prior year tax benefit reconciliation. These immaterial adjustments to the disclosures had no effect on the consolidated balance sheets, statements of operations and cash flows for any periods presented. The Company’s NOL carryforwards were generated from domestic operations. The federal NOLs from the 2013-2017 tax years will expire between 2033 and 2037 and NOLs from 2018-2020 will carryover indefinitely. The state NOLs will expire between 2033 and 2039. Under California Assembly Bill 85, effective June 29, 2020, net operating loss deductions were suspended for tax years beginning in 2020, 2021, and 2022 and the carry forward periods of any net operating losses not utilized due to such suspension were extended. The Company applies the provisions of FASB Accounting Standards Codification (ASC 740-10), “Accounting for Uncertainty in Income Taxes.” ASC 740-10 prescribes a comprehensive model for the recognition, measurement, presentation and disclosure in financial statements of any uncertain tax positions that have been taken or are expected to be taken on a tax return. The Company had unrecognized tax benefits of $2.5 million and none as of December 31, 2020 and 2019, respectively, of which $2.5 million and none, respectively, if recognized would not affect the annual effective tax rate as these unrecognized tax benefits would increase deferred tax assets which would be subject to a full valuation allowance. The Company does not believe that the amount of unrecognized tax benefits will change significantly in the next 12 months. There were no interest or penalties to be recognized for the tax years ended December 31, 2020, 2019, and 2018.

A reconciliation of the beginning and ending balances of unrecognized tax benefits is as follows (in thousands):


Balance at December 31, 2019 and 2018	$	—
Deductions based on tax positions related to prior years	—
Additions based on tax positions related to the current year	2,491
Balance at December 31, 2020	$	2,491

The reconciliation between the Company’s effective tax rate and the statutory tax rate is as follows:


	Years Ended December 31,
	2020		2019		2018
Tax at statutory federal rate	21.0	%	21.0	%	21.0	%
State tax, net of federal benefit	7.0	%	7.0	%	7.0	%
Excess tax benefits related to stock-based compensation	10.3	%	(1.0)	%	(0.4)	%
Section 382 Limitation	—	%	(5.0)	%	—	%
R&D tax credit 100% reserve	(4.5)	%	—	%	—	%
Change in valuation allowance	(36.8)	%	(21.5)	%	(27.4)	%
Other	3.0	%	(0.5)	%	(0.2)	%
Effective tax rate	—	%	—	%	—	%

CARES Act

The CARES Act includes provisions to support businesses in the form of loans, grants, and tax changes, among other types of relief. The Company has reviewed the income tax changes included in the CARES Act, which primarily includes the expansion of the carryback period for NOLs, changes to the deduction and limitation on interest, and acceleration of depreciation for Qualified Improvement Property. The Company has analyzed these changes and does not believe there will be a material effect on the Company’s income tax provision.

- Definition

The entire disclosure for income taxes. Disclosures may include net deferred tax liability or asset recognized in an enterprise's statement of financial position, net change during the year in the total valuation allowance, approximate tax effect of each type of temporary difference and carryforward that gives rise to a significant portion of deferred tax liabilities and deferred tax assets, utilization of a tax carryback, and tax uncertainties information.

+ References + Details

Long-Term Debt (Tables)

12 Months Ended

Dec. 31, 2020

Debt Disclosure [Abstract]

Schedule of Debt, Net of Unamortized Debt Issuance Costs

Debt, net of unamortized debt issuance costs, consists of the following (in thousands) at:


	December 31,
	2020		2019
Debt, principal	$	20,000	$	20,000
Accrued loan fees	1,500		1,500
Debt, total	21,500		21,500
Less: unamortized debt issuance costs	(390)		(1,164)
Debt, net of unamortized debt issuance costs	$	21,110	$	20,336

Schedule of Expected Future Principal Payments for Term Loan

Expected future principal payments for the term loan as of December 31, 2020, are as follows (in thousands):


2021	$	21,500

	$	21,500

- Definition

Tabular disclosure of long-debt instruments or arrangements, including identification, terms, features, collateral requirements and other information necessary to a fair presentation. These are debt arrangements that originally required repayment more than twelve months after issuance or greater than the normal operating cycle of the entity, if longer.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02.22)
-URI http://asc.fasb.org/extlink&oid=120391452&loc=d3e13212-122682

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 835
-SubTopic 30
-Section 45
-Paragraph 1A
-URI http://asc.fasb.org/extlink&oid=119993939&loc=d3e28541-108399

Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 505
-SubTopic 10
-Section 50
-Paragraph 6
-URI http://asc.fasb.org/extlink&oid=109259400&loc=d3e21506-112644

Reference 4: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 235
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.4-08.(e),(f))
-URI http://asc.fasb.org/extlink&oid=120395691&loc=d3e23780-122690

Reference 5: http://fasb.org/us-gaap/role/ref/legacyRef
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-Name Accounting Standards Codification
-Topic 835
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-Section 45
-Paragraph 2
-URI http://asc.fasb.org/extlink&oid=119993939&loc=d3e28551-108399

Reference 6: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 505
-SubTopic 10
-Section 50
-Paragraph 7
-URI http://asc.fasb.org/extlink&oid=109259400&loc=d3e21521-112644

Reference 7: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 505
-SubTopic 10
-Section 50
-Paragraph 8
-URI http://asc.fasb.org/extlink&oid=109259400&loc=d3e21538-112644

Reference 8: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 942
-SubTopic 470
-Section 50
-Paragraph 3
-URI http://asc.fasb.org/extlink&oid=75038535&loc=d3e64711-112823

Reference 9: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 835
-SubTopic 30
-Section 55
-Paragraph 8
-URI http://asc.fasb.org/extlink&oid=114775985&loc=d3e28878-108400

Reference 10: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 505
-SubTopic 10
-Section 50
-Paragraph 3
-URI http://asc.fasb.org/extlink&oid=109259400&loc=d3e21475-112644

+ Details

Noncontrolling Interest	12 Months Ended
Noncontrolling Interest	Dec. 31, 2020
Noncontrolling Interest [Abstract]
Noncontrolling Interest	Noncontrolling Interest For less-than-wholly-owned consolidated subsidiaries, noncontrolling interest is the portion of equity not attributable, directly or indirectly, to the Company. The Company evaluates whether noncontrolling interests possess any redemption features outside of the Company’s control. If such features are determined to exist, the noncontrolling interests are presented outside of permanent equity on our consolidated balance sheets within mezzanine equity. Prior to the Company’s IPO, the Company’s noncontrolling interest related to the portion of Axonics Europe S.A.S. not owned by the Company. The Company presented noncontrolling interest as mezzanine equity on the consolidated balance sheet at December 31, 2017 due to the Share Exchange Agreement that provided the holders of the equity in Axonics Europe S.A.S. (excluding the Company) the unilateral right to exchange its equity interest in Axonics Europe S.A.S. for Preferred Stock of the Company at any time. The Company’s Preferred Stock was presented as mezzanine equity at December 31, 2017, and as such, the rights under the Share Exchange Agreement required the noncontrolling interest to be presented as mezzanine equity as well. Prior to the Company’s IPO, the comprehensive loss attributable to the noncontrolling interest in Axonics Europe S.A.S. were absorbed by the Company since the investors are protected from any losses in this entity due to the conversion right. Changes in amounts attributable to the redeemable noncontrolling interest were presented in the Company’s consolidated statements of mezzanine equity during the year ended December 31, 2017. In conjunction with the Company’s IPO, the interests held by the other investors in Axonics Europe S.A.S. were converted into a fixed number of shares of the Company’s preferred stock pursuant to the terms of the Share Exchange Agreement. These preferred stock shares were then automatically converted into 4,221,715 shares of common stock, and as such, Axonics Europe S.A.S. is the Company’s wholly-owned subsidiary at December 31, 2018.

Nature of Operations and Summary of Significant Accounting Policies (Tables)

12 Months Ended

Dec. 31, 2020

Organization, Consolidation and Presentation of Financial Statements [Abstract]

Schedule of Revenue Disaggregated by Geographic Market

The following table provides additional information pertaining to net revenue disaggregated by geographic market for the years ended December 31, 2020, 2019, and 2018 (in thousands):


	Years Ended December 31,
	2020		2019		2018
United States	$	107,542	$	8,376	$	—
International markets	3,993		5,444		707
Total net revenue	$	111,535	$	13,820	$	707

Schedule of Changes in Allowance for Doubtful Accounts

The following table summarizes the changes in our allowance for doubtful accounts (in thousands):


	Years Ended December 31,
	2020		2019		2018
Balance at beginning of period	$	75	$	—	$	—
Bad debt expense	390		75		—
Balance at end of period	$	465	$	75	$	—

Schedule of Fair Value Hierarchy for Assets Measured on Recurring Basis

The following table presents the fair value hierarchy for those assets measured at fair value on a recurring basis as of December 31, 2019 (in thousands):


	Fair Value Measurements at December 31, 2019
Assets:	Level 1		Level 2		Level 3		Total
Commercial paper	$	—	$	7,195	$	—	$	7,195
Corporate notes	2,018		—		—		2,018
U.S. government and agency securities	3,379		—		—		3,379
	$	5,397	$	7,195	$	—	$	12,592

Consolidated Statements of Comprehensive Loss - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Statement of Comprehensive Income [Abstract]
Net revenue	$ 111,535	$ 13,820	$ 707
Cost of goods sold	44,444	6,490	356
Gross profit	67,091	7,330	351
Operating Expenses
Research and development	29,170	20,181	19,402
General and administrative	25,551	19,076	9,362
Sales and marketing	66,130	48,672	3,724
Total operating expenses	120,851	87,929	32,488
Loss from operations	(53,760)	(80,599)	(32,137)
Other Income (Expense)
Interest income	761	2,974	998
Loss on disposal of property and equipment	(41)	0	0
Interest and other expense	(1,874)	(2,309)	(1,343)
Other income (expense), net	(1,154)	665	(345)
Loss before income tax expense	(54,914)	(79,934)	(32,482)
Income tax expense	1	1	1
Net loss	(54,915)	(79,935)	(32,483)
Foreign currency translation adjustment	(3)	(12)	(14)
Comprehensive loss	$ (54,918)	$ (79,947)	$ (32,497)
Net loss per share, basic and diluted (USD per share)	$ (1.48)	$ (2.80)	$ (4.64)
Weighted-average shares used to compute basic and diluted net loss per share (shares)	36,981,335	28,567,302	6,997,777

Income Taxes - Net Deferred Tax Assets (Details) - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019
Income Tax Disclosure [Abstract]
Compensation accruals	$ 592	$ 404
Depreciation and amortization	145	48
Lease liability	901	252
Net operating loss carryforwards	59,176	41,564
Other	4,438	3,752
Total deferred tax assets	65,252	46,020
Less: valuation allowance	(65,252)	(46,020)
Total net deferred tax assets	$ 0	$ 0

Related Party Transactions	12 Months Ended
Related Party Transactions	Dec. 31, 2020
Related Party Transactions [Abstract]
Related Party Transactions	Related Party Transactions The Company has a License Agreement and corresponding royalties incurred with AMF, which is also a stockholder of the Company. For additional information, see Note 4. The 2014 Plan allowed for certain members of management to purchase vested options and unvested options (subject to repurchase rights) through a full recourse promissory note and stock pledge agreement. The promissory notes outstanding were recorded as “Stock subscriptions receivable” in the accompanying consolidated balance sheet. On October 4, 2018, the Company entered into agreements with certain officers and directors to terminate each of their respective promissory notes and to forgive all respective obligations for payment thereof in connection with the Company’s IPO. As a result, on October 4, 2018, the Company forgave all outstanding stock subscriptions receivable referenced above in the aggregate amount of $1.8 million plus accrued interest, which amount was recorded as compensation expense.

Income Taxes - Effective Income Tax Rate Reconciliation (Details)	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Income Tax Disclosure [Abstract]
Tax at statutory federal rate (as a percent)	21.00%	21.00%	21.00%
State tax, net of federal benefit (as a percent)	7.00%	7.00%	7.00%
Excess tax benefits related to stock-based compensation (as a percent)	10.30%	(1.00%)	(0.40%)
Section 382 Limitation (as a percent)	0.00%	(5.00%)	0.00%
R&D tax credit 100% reserve (as a percent)	(4.50%)	0.00%	0.00%
Change in valuation allowance (as a percent)	(36.80%)	(21.50%)	(27.40%)
Other (as a percent)	3.00%	(0.50%)	(0.20%)
Effective tax rate (as a percent)	0.00%	0.00%	0.00%

Income Taxes (Tables)

12 Months Ended

Dec. 31, 2020

Income Tax Disclosure [Abstract]

Schedule of Net Deferred Tax Assets

Significant components of the Company’s net deferred tax assets are as follows (in thousands) as of:


	December 31,
	2020		2019
Compensation accruals	$	592	$	404
Depreciation and amortization	145		48
Lease liability	901		252
Net operating loss carryforwards	59,176		41,564

Other	4,438		3,752
Total deferred tax assets	65,252		46,020
Less: valuation allowance	(65,252)		(46,020)
Total net deferred tax assets	$	—	$	—

Schedule of Unrecognized Tax Benefits Roll Forward

A reconciliation of the beginning and ending balances of unrecognized tax benefits is as follows (in thousands):


Balance at December 31, 2019 and 2018	$	—
Deductions based on tax positions related to prior years	—
Additions based on tax positions related to the current year	2,491
Balance at December 31, 2020	$	2,491

Schedule of Effective Income Tax Rate Reconciliation

The reconciliation between the Company’s effective tax rate and the statutory tax rate is as follows:


	Years Ended December 31,
	2020		2019		2018
Tax at statutory federal rate	21.0	%	21.0	%	21.0	%
State tax, net of federal benefit	7.0	%	7.0	%	7.0	%
Excess tax benefits related to stock-based compensation	10.3	%	(1.0)	%	(0.4)	%
Section 382 Limitation	—	%	(5.0)	%	—	%
R&D tax credit 100% reserve	(4.5)	%	—	%	—	%
Change in valuation allowance	(36.8)	%	(21.5)	%	(27.4)	%
Other	3.0	%	(0.5)	%	(0.2)	%
Effective tax rate	—	%	—	%	—	%

Consolidated Statements of Cash Flows - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Cash Flows from Operating Activities
Net loss	$ (54,915)	$ (79,935)	$ (32,483)
Adjustments to reconcile net loss to net cash used in operating activities
Depreciation and amortization	1,741	1,191	946
Loss on disposal of property and equipment	41	0	0
Stock-based compensation	15,095	8,720	606
Amortization of debt issuance costs	774	873	338
Provision for doubtful accounts	390	75	0
Forgiveness of stock subscriptions receivable	0	0	1,824
Change in fair value of warrants	0	0	254
Other items	165	0	0
Changes in operating assets and liabilities
Accounts receivable	(10,781)	(7,527)	(427)
Inventory	(47,353)	(11,986)	(2,255)
Prepaid expenses and other current assets	(863)	(752)	(3,009)
Other assets	(90)	(299)	65
Accounts payable	4,778	2,446	1,820
Accrued liabilities	4,193	1,155	846
Accrued compensation and benefits	2,573	2,711	214
Lease liability	510	(126)	(109)
Net cash used in operating activities	(83,742)	(83,454)	(31,370)
Cash Flows from Investing Activities
Purchases of property and equipment	(2,938)	(1,339)	(1,228)
Purchases of short-term investments	0	(36,404)	(78,122)
Proceeds from sales and maturities of short-term investments	12,592	83,030	19,300
Net cash provided by (used in) investing activities	9,654	45,287	(60,050)
Cash Flows from Financing Activities
Payment of debt issuance costs	0	0	(142)
Proceeds from debt	0	0	20,000
Proceeds from exercise of stock options	3,703	506	9
Proceeds from issuance of preferred stock and noncontrolling interest	0	0	20,098
Repurchase of common stock	0	0	(473)
Net cash provided by financing activities	144,190	110,955	165,342
Effect of exchange rate changes on cash and cash equivalents	(3)	(12)	(14)
Net increase in cash and cash equivalents	70,099	72,776	73,908
Cash and cash equivalents, beginning of year	171,082	98,306	24,398
Cash and cash equivalents, end of year	241,181	171,082	98,306
Supplemental Disclosure of Cash Flow Information
Cash paid for interest	1,102	1,436	751
Cash paid for taxes	1	1	1
Noncash Investing and Financing Activities
Common stock issuance on stock option exercises for promissory notes	0	0	71
Warrants issued as debt issuance costs	0	0	733
Accrued loan fees as debt issuance costs	0	0	1,500
Forgiveness of stock subscriptions receivable	0	0	1,824
Preferred Stock
Cash Flows from Financing Activities
Payment of issuance costs	0	0	(199)
Follow-on Offering
Cash Flows from Financing Activities
Proceeds from issuance of common stock upon initial public offering / follow-on offering	149,500	117,590	0
Follow-on Offering \| Common Stock
Cash Flows from Financing Activities
Payment of issuance costs	(9,013)	(7,141)	0
Initial Public Offering
Cash Flows from Financing Activities
Proceeds from issuance of common stock upon initial public offering / follow-on offering	0	0	138,000
Initial Public Offering \| Common Stock
Cash Flows from Financing Activities
Payment of issuance costs	$ 0	$ 0	$ (11,951)

Property and Equipment

12 Months Ended

Dec. 31, 2020

Property, Plant and Equipment [Abstract]

Property and Equipment

Property and equipment, net consists of the following (in thousands) at:


	December 31,
	2020		2019
Research and development equipment	$	1,205	$	1,086
Computer hardware and software	2,286		1,418
Tools and molds	1,404		1,303
Leasehold improvements	3,759		1,500
Furniture and fixtures	1,360		624
Construction in progress	129		176
	10,143		6,107
Less: accumulated depreciation and amortization	(3,815)		(3,060)
	$	6,328	$	3,047

Depreciation and amortization expense of property and equipment was $1.6 million, $1.1 million, and $0.8 million for the years ended December 31, 2020, 2019, and 2018, respectively.

Income Taxes - Reconciliation of Unrecognized Tax Benefits (Details) $ in Thousands	12 Months Ended
	Dec. 31, 2020 USD ($)
Reconciliation of Unrecognized Tax Benefits, Excluding Amounts Pertaining to Examined Tax Returns [Roll Forward]
Balance at beginning of period	$ 0
Deductions based on tax positions related to prior years	0
Additions based on tax positions related to the current year	2,491
Balance at end of period	$ 2,491

Stockholders' Equity - Stock Option Narrative (Details) - USD ($) $ / shares in Units, $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Options grants in period, weighted average grant date fair value (USD per share)	$ 18.56	$ 13.79	$ 3.62
Unrecognized compensation cost, period for recognition	4 years
Options outstanding weighted average remaining contractual term	7 years 8 months 12 days	7 years 7 months 6 days
Stock Option
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Unrecognized compensation cost	$ 11.6	$ 19.5
Unrecognized compensation cost, period for recognition	2 years 4 months 24 days	3 years 2 months 12 days
2014 Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock reserved for issuance (shares)	3,131,624	3,156,295
Options and restricted stock-based awards remaining for future issuance (shares)	0	0
2018 Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock reserved for issuance (shares)	4,562,317
Options and restricted stock-based awards remaining for future issuance (shares)	1,678,326	1,965,500

Nature of Operations and Summary of Significant Accounting Policies - Narrative (Details)					1 Months Ended	12 Months Ended				96 Months Ended
	May 20, 2020 USD ($) $ / shares shares	Nov. 22, 2019 USD ($) $ / shares shares	Nov. 02, 2018 USD ($) $ / shares shares	Oct. 31, 2018 shares	Oct. 31, 2018 $ / shares shares	Dec. 31, 2020 USD ($) shares	Dec. 31, 2019 USD ($) shares	Dec. 31, 2018 USD ($) shares	Dec. 31, 2013 USD ($) shares	Dec. 31, 2020 USD ($) shares	Nov. 30, 2018 shares	Oct. 30, 2018 shares
Basis of Presentation:
Common stock authorized (shares) \| shares				20,500,000	20,500,000	50,000,000	50,000,000			50,000,000	50,000,000	17,500,000
Stock split ratio					1.2
Qualified IPO minimum share price (USD per share) \| $ / shares					$ 12.00
Preferred stock authorized (shares) \| shares						10,000,000	10,000,000			10,000,000	10,000,000
Revenue Recognition:
Allowance for product returns						$ 300,000	$ 0			$ 300,000
Replacement costs						100,000	0	$ 0
Investment Securities:
Unrealized gains (losses) on available-for-sale securities						0	0	0
Outstanding investment securities						0	12,592,000			0
Inventory:
Finished goods inventory						42,100,000	7,000,000.0			42,100,000
Work-in-process inventory						3,500,000	1,500,000			3,500,000
Raw materials inventory						17,500,000	7,200,000			17,500,000
Inventory reserves						0	100,000			0
Intangible Asset:
Shares issued for purchase of intangible asset (shares) \| shares									50,000
Fair value of shares issued for purchase of intangible asset									$ 1,000,000.0
Finite-lived intangible asset acquired									$ 1,000,000.0
Finite-lived intangible assets, weighted-average amortization period									8 years 8 months 15 days
Impairment of finite-lived intangible asset										$ 0
Impairment of Long-Lived Assets:
Impairment of long-lived assets						0
Advertising Expense:
Advertising expense						$ 2,900,000	$ 2,600,000	$ 1,100,000
Stock-Based Compensation:
Unrecognized compensation cost, period for recognition						4 years
Net Loss per Share of Common Stock:
Potentially dilutive weighted-average shares not included in computation of diluted weighted-average shares (in shares) \| shares						2,300,982	1,737,430	9,192,127
Minimum
Inventory:
Inventory shelf life						12 months
Property and Equipment:
Property and equipment useful life						3 years
Maximum
Inventory:
Inventory shelf life						36 months
Property and Equipment:
Property and equipment useful life						7 years
Initial Public Offering
Initial Public Offering:
Stock issued (shares) \| shares			9,200,000
Sale of stock, stock price (USD per share) \| $ / shares			$ 15.00
Net proceeds from sale of stock			$ 126,000,000.0
Common Stock Issued upon Exercise of Underwriters Option
Initial Public Offering:
Stock issued (shares) \| shares	600,000	750,000	1,200,000
Follow-on Offering
Initial Public Offering:
Stock issued (shares) \| shares	4,600,000	5,345,000
Sale of stock, stock price (USD per share) \| $ / shares	$ 32.50	$ 22.00
Net proceeds from sale of stock	$ 140,500,000	$ 110,400,000
Common Stock
Initial Public Offering:
Conversion of preferred stock to common stock (shares) \| shares			15,813,297	15,813,297				15,813,297
Number of common stock warrants converted from preferred stock warrants (shares) \| shares			80,000	80,000	80,000
Stock Option and Restricted Stock-Based Awards
Stock-Based Compensation:
Vesting period						4 years
Restricted Stock Units
Stock-Based Compensation:
Unrecognized compensation cost, period for recognition						10 months 24 days	1 year 6 months
Vesting period						1 year

Income Taxes - Narrative (Details) - USD ($)	12 Months Ended
Income Taxes - Narrative (Details) - USD ($)	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Income Tax Contingency [Line Items]
Annual effective tax rate (as a percent)	0.00%	0.00%	0.00%
Operating loss carryforwards	$ 213,500,000
Reduction in net operating loss carryforwards	12,200,000
Increase (decrease) in valuation allowance	19,200,000
Valuation allowance	65,252,000	$ 46,020,000
Deferred tax assets	65,252,000	46,020,000
Unrecognized tax benefits	2,491,000	0	$ 0
Unrecognized tax benefits that would not impact effective tax rate	2,500,000	0
Interest or penalties to be recognized for the period	0	0	$ 0
Revision of Prior Period, Adjustment
Income Tax Contingency [Line Items]
Valuation allowance		(3,900,000)
Deferred tax assets		$ (3,900,000)
Research Tax Credit Carryforward
Income Tax Contingency [Line Items]
Reduction in R&D tax credits	$ 1,500,000

Stockholders' Equity (Tables)

12 Months Ended

Dec. 31, 2020

Equity [Abstract]

Schedule of Stock-based Compensation Expense

Stock-based compensation expense included in the Company’s consolidated statements of comprehensive loss is allocated as follows (in thousands):


	Years Ended December 31,
	2020		2019		2018
Research and development	$	3,457	$	1,725	$	197
General and administrative	5,852		3,950		361
Sales and marketing	5,786		3,045		48
	$	15,095	$	8,720	$	606

Schedule of Common Stock Reserved for Future Issuance

The Company had shares of common stock reserved for future issuance as follows at:


	December 31,
	2020	2019

Options outstanding under the 2014 Plan	501,598	1,126,140

Options and restricted stock-based awards outstanding under the 2018 Plan	2,477,929	2,560,232
Options and restricted stock-based awards remaining under the 2018 Plan for future issuance	1,678,326	1,965,500
	4,657,853	5,651,872

Schedule of Stock Option Award Valuation Assumptions


	Years Ended December 31,
	2020	2019	2018
Expected term (in years)	6.05	5.07 - 6.16	5.00 - 6.96
Stock volatility	72.01%	70.02% - 77.52%	68.04% - 77.03%
Risk-free interest rate	1.37%	1.42% - 2.56%	2.26% - 3.07%
Dividend rate	—	—	—

Schedule of Stock Option Activity

The following table summarizes stock option activity under the 2014 and 2018 Plans (in thousands, except share and per share data):


	Number of Options	Weighted-Average Exercise Price Per Share		Aggregate Intrinsic Value



Outstanding at December 31, 2017	903,857	$	1.18
Options granted	668,380	3.55
Options exercised	(55,840)	1.47		$	23	(1)
Options forfeited	(2,050)	1.23
Outstanding at December 31, 2018	1,514,347	2.22
Options granted	1,671,044	21.28
Options exercised	(281,744)	1.79		$	7,386	(1)
Options forfeited	(56,546)	13.43
Outstanding at December 31, 2019	2,847,101	13.22
Options granted	5,000	29.03
Options exercised	(767,792)	5.05		$	25,066	(1)
Options forfeited	(129,066)	20.20
Outstanding at December 31, 2020	1,955,243	$	16.01	$	66,302	(2)
Options exercisable at December 31, 2020	906,457	$	14.30	$	32,287	(2)

_____________________________________________

(1) Represents the total difference between the Company’s closing stock price at the time of exercise and the stock option exercise price, multiplied by the number of options exercised.

Schedule of Restricted Shares Awards and Restricted Stock Units Activity

The following table summarizes restricted shares awards activity:


	Number of Restricted Shares Awards	Weighted-Average Fair Value Per Share at Grant Date
Outstanding at December 31, 2017	—	$	—
Restricted shares awards granted	50,000	14.48
Outstanding at December 31, 2018	50,000	14.48
Restricted shares awards granted	580,667	24.08
Restricted shares awards vested	(27,551)	18.80
Restricted shares awards forfeited	(16,950)	21.09
Outstanding at December 31, 2019	586,166	23.59
Restricted shares awards granted	502,500	37.68
Restricted shares awards vested	(174,890)	23.29
Restricted shares awards forfeited	(96,593)	28.83
Outstanding at December 31, 2020	817,183	$	31.70

The following table summarizes restricted stock units activity:


	Number of Restricted Stock Units	Weighted-Average Fair Value Per Share at Grant Date
Outstanding at December 31, 2018	—	$	—
Restricted stock units granted	248,104	21.48
Outstanding at December 31, 2019	248,104	21.48
Restricted stock units granted	8,000	29.03
Restricted stock units vested	(46,336)	14.19
Restricted stock units forfeited	(2,667)	14.19
Outstanding at December 31, 2020	207,101	$	23.49

Consolidated Statements of Mezzanine Equity - (Parenthetical) - Series C Convertible Preferred Stock $ in Thousands	12 Months Ended
	Dec. 31, 2018 USD ($) $ / shares
Preferred stock issuance, price per share (USD per share) \| $ / shares	$ 9.00
Issuance costs \| $	$ 199

Long-Term Debt - Narrative (Details)	1 Months Ended		12 Months Ended
Long-Term Debt - Narrative (Details)	Jan. 31, 2021	Feb. 28, 2018 USD ($) tranch	Dec. 31, 2020 USD ($)	Dec. 31, 2019 USD ($)	Oct. 31, 2018 USD ($)
Debt Instrument [Line Items]
Face amount of debt instrument			$ 20,000,000	$ 20,000,000
Voting capital stock of foreign subsidiaries excluded from first priority lien (more than) (as a percent)			65.00%
Term Loans \| Term Loan due 2021
Debt Instrument [Line Items]
Long-term debt issuable		$ 20,000,000.0
Number of tranches \| tranch		3
Maximum prepayments of amounts outstanding allowed			$ 5,000,000.0
Period of prior written notice before prepayment of amounts outstanding			30 days
Final payment fee (as a percent)			7.50%
Term Loans \| Term Loan due 2021 \| Subsequent Event
Debt Instrument [Line Items]
Final payment fee (as a percent)	7.50%
Term Loans \| Term Loan due 2021 \| Period One
Debt Instrument [Line Items]
Prepayment fee (as a percent)			3.00%
Term Loans \| Term Loan due 2021 \| Period Two
Debt Instrument [Line Items]
Prepayment fee (as a percent)			2.00%
Term Loans \| Term Loan due 2021 \| Period Three
Debt Instrument [Line Items]
Prepayment fee (as a percent)			1.00%
Term Loans \| Term Loan due 2021 \| Prime Rate
Debt Instrument [Line Items]
Basis spread on variable rate (as a percent)		1.75%
Term Loans \| Term Loan due 2021 - Tranche A
Debt Instrument [Line Items]
Face amount of debt instrument		$ 10,000,000.0
Term Loans \| Term Loan due 2021 - Tranche B & C
Debt Instrument [Line Items]
Face amount of debt instrument					$ 10,000,000.0
Term Loans \| Term Loan due 2021 - Tranche B
Debt Instrument [Line Items]
Long-term debt issuable		5,000,000.0
Face amount of debt instrument					5,000,000.0
Term Loans \| Term Loan due 2021 - Tranche C
Debt Instrument [Line Items]
Long-term debt issuable		5,000,000.0
Face amount of debt instrument					$ 5,000,000.0
Minimum gross proceeds from sale of equity securities		$ 20,000,000.0
Term Loans \| Second Amendment
Debt Instrument [Line Items]
Non-refundable fee				$ 200,000

Nature of Operations and Summary of Significant Accounting Policies - Fair Value Hierarchy (Details) - USD ($)	Dec. 31, 2020	Dec. 31, 2019
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments	$ 0	$ 12,592,000
Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments		5,397,000
Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments		7,195,000
Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments		0
Commercial paper
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments		7,195,000
Commercial paper \| Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments		0
Commercial paper \| Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments		7,195,000
Commercial paper \| Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments		0
Corporate notes
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments		2,018,000
Corporate notes \| Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments		2,018,000
Corporate notes \| Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments		0
Corporate notes \| Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments		0
U.S. government and agency securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments		3,379,000
U.S. government and agency securities \| Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments		3,379,000
U.S. government and agency securities \| Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments		0
U.S. government and agency securities \| Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments		$ 0

Long-Term Debt - Expected Future Principal Payments for Term Loan (Details) - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019
Debt Disclosure [Abstract]
2021	$ 21,500
Debt, total	$ 21,500	$ 21,500

Intangible Asset - Estimated Future Amortization Expense (Details) - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019
Finite-Lived Intangible Assets, Amortization Expense, Maturity Schedule [Abstract]
2021	$ 115
2022	81
Estimated future amortization expense	$ 196	$ 311

Stockholders' Equity - Restricted Shares Awards Activity (Details) - Restricted Shares Awards - $ / shares	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Number of Restricted Shares Awards
Outstanding at beginning of period (shares)	586,166	50,000	0
Granted (shares)	502,500	580,667	50,000
Vested (shares)	(174,890)	(27,551)
Forfeited (shares)	(96,593)	(16,950)
Outstanding at end of period (shares)	817,183	586,166	50,000
Weighted-Average Fair Value Per Share at Grant Date
Outstanding at beginning of period (USD per share)	$ 23.59	$ 14.48	$ 0
Granted (USD per share)	37.68	24.08	14.48
Vested (USD per share)	23.29	18.80
Forfeited (USD per share)	28.83	21.09
Outstanding at end of period (USD per share)	$ 31.70	$ 23.59	$ 14.48

Employee Benefit Plan - Narrative (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Retirement Benefits [Abstract]
Contributions by employer	$ 1.6	$ 1.1	$ 0.3

Nature of Operations and Summary of Significant Accounting Policies

12 Months Ended

Dec. 31, 2020

Organization, Consolidation and Presentation of Financial Statements [Abstract]

Nature of Operations and Summary of Significant Accounting Policies

Nature of Operations

Axonics Modulation Technologies, Inc. (the Company), formerly American Restorative Medicine, Inc., was incorporated in the state of Delaware on March 2, 2012. The Company had no operations until October 1, 2013, when the license agreement between Alfred E. Mann Foundation for Scientific Research (AMF) and the Company (the License Agreement) was entered into. The Company is a medical technology company that has developed and is commercializing innovative and minimally invasive implantable neurostimulation systems. The Company has designed and developed the rechargeable sacral neuromodulation (SNM) system (r-SNM System), which delivers mild electrical pulses to the targeted sacral nerve in order to restore normal communication to and from the brain to reduce the symptoms of overactive bladder (OAB), urinary retention (UR) and fecal incontinence (FI). The r-SNM System is protected by intellectual property based on Company-generated innovations and patents and other intellectual property licensed from AMF. The Company has marketing approvals in the United States, Europe, Canada, and Australia for all relevant clinical indications. The premarket approval (PMA) application for the r-SNM System for the treatment of FI was approved by the U.S. Food and Drug Administration (FDA) on September 6, 2019, and the PMA application for the r-SNM System for the treatment of OAB and UR was approved by the FDA on November 13, 2019. Accordingly, the Company began U.S. commercialization of its r-SNM System in the fourth quarter of 2019. Prior to the fourth quarter of 2019, the Company derived revenue only from its international operations in select markets including England, the Netherlands and Canada, and its activities have consisted primarily of developing the r-SNM System, conducting its RELAX-OAB post-market clinical follow-up study in Europe, its ARTISAN-SNM pivotal clinical study in the United States and hiring and training its U.S. commercial team in preparation for the launch of the r-SNM System in the United States.

Initial Public Offering

On November 2, 2018, the Company completed its initial public offering (IPO) by issuing 9,200,000 shares of common stock, at an offering price of $15.00 per share, inclusive of 1,200,000 shares of the Company’s common stock issued upon the exercise by the underwriters of their option to purchase additional shares. The net proceeds were approximately $126.0 million, after deducting underwriting discounts, commissions and offering expenses payable by the Company. In connection with the IPO, the Company’s outstanding shares of convertible preferred stock were automatically converted into an aggregate of 15,813,297 shares of common stock, and the Company’s outstanding warrants to purchase shares of Series C convertible preferred stock were automatically converted into warrants to purchase up to an aggregate of 80,000 shares of common stock (see Note 6).

November 2019 Follow-On Offering

On November 22, 2019, the Company completed a follow-on offering by issuing 5,345,000 shares of common stock, at an offering price of $22.00 per share, inclusive of 750,000 shares of the Company’s common stock issued upon the exercise by the underwriters of their option to purchase additional shares. The net proceeds to the Company were approximately $110.4 million, after deducting underwriting discounts, commissions and offering expenses payable by the Company.

May 2020 Follow-On Offering

On May 12, 2020, the Company completed a follow-on offering by issuing 4,600,000 shares of common stock, at an offering price of $32.50 per share, inclusive of 600,000 shares of the Company’s common stock issued upon the exercise by the underwriters of their option to purchase additional shares. The net proceeds to the Company were approximately $140.5 million, after deducting underwriting discounts, commissions and offering expenses payable by the Company.

Principles of Consolidation

The accompanying consolidated financial statements include the accounts of the Company, its wholly-owned subsidiaries, Axonics Europe, S.A.S., Axonics Modulation Technologies U.K. Limited and Axonics Modulation Technologies Australia Pty Ltd. Intercompany accounts and transactions have been eliminated in consolidation.

Basis of Presentation

The accompanying consolidated financial statements have been prepared in accordance with accounting principles generally accepted in the United States (GAAP). Certain prior year reported amounts have been reclassified to conform with the 2020 presentation.

Stock Split and Charter Amendment

In October 2018, the board of directors and certain stockholders of the Company approved an amendment to the Company’s Certificate of Incorporation to (i) increase the authorized shares of common stock from 17,500,000 to 20,500,000, (ii) effect a 1.2-for-1 forward stock split of the Company’s common stock and (iii) define a “Qualified IPO” to include a per share price equal to at least $12.00 (as adjusted for stock splits, combinations, stock dividends, recapitalizations and the like). All shares of common stock, stock options, and per share information presented in the consolidated financial statements have been adjusted to reflect the stock split on a retroactive basis for all periods presented. Any fractional shares that resulted from the stock split were rounded up to the nearest whole share. There was no change in the par value of the Company’s common stock. The ratios by which shares of preferred stock are convertible into shares of common stock have been adjusted to reflect the effects of the forward stock split.

In November 2018, the board of directors and certain stockholders of the Company approved an amendment to the Company’s Certificate of Incorporation to increase the authorized shares of common stock from 20,500,000 to 50,000,000 and authorize 10,000,000 shares of preferred stock.

COVID-19

The recent COVID-19 outbreak, and the resulting restrictions intended to slow the spread of COVID-19, including stay-at-home orders, business shutdowns and other restrictions, has adversely affected the Company’s business in several ways. The primary impact on the Company’s business was the cancellation or delay of elective procedures in certain areas to allow health care facilities to prioritize the treatment of COVID-19 patients during the initial stages of the pandemic or because patients are avoiding health care facilities that they feel are unsafe. These developments materially reduced the number of procedures using the Company’s r-SNM System. If governmental authorities recommend that it is deemed advisable for health care facilities to not perform outpatient elective procedures as was the case in late March and April of 2020, the Company expects it would materially harm the Company’s revenues and potentially increase the Company’s operating loss. These challenges will likely continue for the duration of the pandemic and could reduce our revenue and negatively impact our business, financial condition and results of operations while the pandemic continues. If these delays in procedures occur in the future, the Company may have to scale back its business, including reducing headcount, which could have a negative impact on the Company’s long-term operations. The Company could also experience other negative impacts of the COVID-19 outbreak such as the lack of availability of the Company’s key personnel, temporary closures of the Company’s office or the facilities of the Company’s business partners, customers, third party service providers or other vendors, and the interruption of the Company’s supply chain, distribution channels, liquidity and capital or financial markets.

Any disruption and volatility in the global capital markets as a result of the pandemic may increase the Company’s cost of capital and adversely affect the Company’s ability to access financing when and on terms that the Company desires. In addition, a recession resulting from the spread of COVID-19 could materially affect the Company’s business, especially if a recession results in higher unemployment causing potential patients to not have access to health insurance.

The ultimate extent to which the COVID-19 pandemic and its repercussions impact the Company’s business will depend on future developments, which are highly uncertain. However, the foregoing and other continued disruptions to the Company’s business as a result of COVID-19 could result in a material adverse effect on the Company’s business, results of operations, financial condition and cash flows.

Use of Estimates

The preparation of consolidated financial statements in conformity with GAAP requires the Company’s management to make estimates and judgments that affect the reported amounts of assets, liabilities, and expenses, and related disclosure of contingent assets and liabilities. The Company bases its estimates on historical experience

and on various other assumptions that it believes to be reasonable under the circumstances. The results of this evaluation then form the basis for making judgments about the carrying values of assets and liabilities that are not readily apparent from other sources. Actual results may differ from these estimates under different assumptions or conditions, and such differences may be material to the consolidated financial statements.

Revenue Recognition

Revenue recognized during the years ended December 31, 2020, 2019, and 2018 relates entirely to the sale of our r-SNM System.

The Company has revenue arrangements that consist of a single performance obligation. The Company recognizes revenue at the point in time when it transfers control of promised goods to its customers. Revenue is measured as the amount of consideration it expects to receive in exchange for transferring goods. The amount of revenue that is recognized is based on the transaction price, which represents the invoiced amount and includes estimates of variable consideration such as discounts, where applicable. The Company does not offer rights of return or price protection. The amount of variable consideration included in the transaction price may be constrained and is included only to the extent that it is probable that a significant reversal in the amount of the cumulative revenue recognized under the contract will not occur in a future period. Payment terms, typically less than three months, are offered to the Company’s customers and do not include a significant financing component. The Company extends credit to its customers based upon an evaluation of the customer’s financial condition and credit history and generally requires no collateral. The Company does not have any contract balances related to product sales. The Company also does not have significant contract acquisition costs related to product sales.

In accordance with Company policy and based on the Company’s historical experience, the allowance for product returns was $0.3 million and zero at December 31, 2020 and 2019, respectively. Damaged or defective products are replaced at no charge under the Company’s standard warranty. For the years ended December 31, 2020, 2019, and 2018, the replacement costs were $0.1 million, minimal, and zero, respectively.

Shipping and handling costs incurred for the delivery of goods to customers are included in cost of goods sold. Amounts billed to customers for shipping and handling are included in net revenue.

The following table provides additional information pertaining to net revenue disaggregated by geographic market for the years ended December 31, 2020, 2019, and 2018 (in thousands):


	Years Ended December 31,
	2020		2019		2018
United States	$	107,542	$	8,376	$	—
International markets	3,993		5,444		707
Total net revenue	$	111,535	$	13,820	$	707

Allowance for Doubtful Accounts

The Company makes estimates of the collectability of accounts receivable. Upon adoption of ASU 2016-13, the Company did not recognize an adjustment to the beginning balance of retained earnings as the impact from adoption was not material. The Company’s estimate of future losses is made by management based upon historical bad debts, customer receivable balances, age of customer receivable balances, customers’ financial conditions and reasonable forecasted economic trends. Despite the Company’s efforts to minimize credit risk exposure, clients could be adversely affected if future economic and industry trends, including those related to COVID-19, change in such a manner as to negatively impact their cash flows. The full effects of COVID-19 on the Company’s clients are highly uncertain and cannot be predicted. As a result, the Company’s future collection experience can differ significantly from historical collection trends. If the Company’s clients experience a negative impact on their cash flows, it could have a material adverse effect on the Company’s results of operations and financial condition.

The following table summarizes the changes in our allowance for doubtful accounts (in thousands):


	Years Ended December 31,
	2020		2019		2018
Balance at beginning of period	$	75	$	—	$	—
Bad debt expense	390		75		—
Balance at end of period	$	465	$	75	$	—

Cash and Cash Equivalents

Cash equivalents consist of short-term, highly liquid investments purchased with an original maturity of three months or less. Financial instruments that potentially subject the Company to a concentration of credit risk consist of cash and cash equivalents. At times, the cash and cash equivalent balances may exceed federally insured limits. The Company does not believe that this results in any significant credit risk as the Company’s policy is to place its cash and cash equivalents in highly-rated financial institutions.

Fair Value of Financial Instruments

Fair value is defined as the price that would be received to sell an asset or paid to transfer a liability in an orderly transaction between market participants at the measurement date. A three-level fair value hierarchy prioritizes the inputs used to measure fair value. The hierarchy requires entities to maximize the use of observable inputs and minimize the use of unobservable inputs. The three levels of inputs used to measure fair value are as follows:

•Level 1: Inputs are unadjusted quoted prices in active markets for identical assets or liabilities.

•Level 2: Inputs are quoted prices for similar assets and liabilities in active markets or quoted prices for identical or similar instruments in markets that are not active and model-derived valuations in which all significant inputs and significant value drivers are observable in active markets.

•Level 3: Inputs are unobservable inputs based on the Company’s assumptions and valuation techniques used to measure assets and liabilities at fair value. The inputs require significant management judgment or estimation. The Company’s assessment of the significance of an input to the fair value measurement requires judgment, which may affect the valuation of fair value assets and liabilities and their placement within the fair value hierarchy levels. The carrying amounts reported in the consolidated financial statements approximate the fair value for cash and cash equivalents, accounts receivable, accounts payables, and accrued expenses, due to their short-term nature. The carrying amount of the Company’s term loan, which is described below, approximates fair value, considering the interest rates are based on the prime interest rate.

Investment Securities

The Company classifies its investment securities as available-for-sale. Those investments in debt securities with maturities less than 12 months at the date of purchase are considered short-term investments. Those investments in debt securities with maturities greater than 12 months at the date of purchase are considered long-term investments. The Company’s investment securities classified as available-for-sale are recorded at fair value based on the fair value hierarchy (Level 1 and Level 2 inputs in the fair value hierarchy), and consists primarily of commercial paper, corporate notes and U.S. government and agency securities. Unrealized gains or losses, deemed temporary in nature, are reported as other comprehensive income within the consolidated statement of comprehensive income (loss). There were no unrealized gains or losses during the years ended December 31, 2020, 2019, and 2018.

A decline in the fair value of any security below cost that is deemed other than temporary results in a charge to net income (loss) and the corresponding establishment of a new cost basis for the security. Premiums (discounts) are amortized (accreted) over the life of the related security as an adjustment to yield using the straight-line interest method. Dividend and interest income are recognized when earned. Realized gains or losses are

included in net income (loss) and are derived using the specific identification method for determining the cost of securities sold.

The Company had no outstanding investment securities as of December 31, 2020. The following table presents the fair value hierarchy for those assets measured at fair value on a recurring basis as of December 31, 2019 (in thousands):


	Fair Value Measurements at December 31, 2019
Assets:	Level 1		Level 2		Level 3		Total
Commercial paper	$	—	$	7,195	$	—	$	7,195
Corporate notes	2,018		—		—		2,018
U.S. government and agency securities	3,379		—		—		3,379
	$	5,397	$	7,195	$	—	$	12,592

Foreign Currency Translation

The functional currencies of the Company’s subsidiaries are currencies other than the U.S. dollar. The Company translates assets and liabilities of the foreign subsidiaries into U.S. dollars at the exchange rate in effect on the balance sheet date. Costs and expenses of the subsidiaries are translated into U.S. dollars at the average exchange rate during the period. Gains or losses from these translation adjustments are reported as a separate component of stockholders’ equity in accumulated other comprehensive loss until there is a sale or complete or substantially complete liquidation of the Company’s investment in the foreign subsidiary at which time the gains or losses will be realized and included in net income (loss). As of December 31, 2020 and 2019, all foreign currency translation gains (losses) have been unrealized and included in accumulated other comprehensive loss. Accumulated other comprehensive loss consists entirely of losses or gains from translation of foreign subsidiaries at December 31, 2020 and 2019. Foreign currency transaction gains and losses are included in results of operations and have not been significant for the periods presented.

Inventory, Net

Inventories are stated at the lower of cost or net realizable value, with cost computed on a first-in, first-out basis. The Company reduces the carrying value of inventories for items that are potentially excess, obsolete, or slow-moving based on changes in customer demand, technology developments, or other economic factors.

The Company capitalizes inventory produced for commercial sale. The Company capitalizes manufacturing costs as inventory following both the receipt of regulatory approval from regulatory bodies and the Company’s intent to commercialize. Costs associated with developmental products prior to satisfying the Company’s inventory capitalization criteria are charged to research and development expense as incurred.

Products that have been approved by certain regulatory authorities are also used in clinical programs to assess the safety and efficacy of the products for usage that have not been approved by the FDA or other regulatory authorities. The form of product utilized for both commercial and certain clinical programs is identical and, as a result, the inventory has an “alternative future use” as defined in authoritative guidance. Component materials and purchased products associated with clinical development programs are included in inventory and charged to research and development expense when the product enters the research and development process and no longer can be used for commercial purposes and, therefore, does not have an “alternative future use.”

For products that are under development and have not yet been approved by regulatory authorities, purchased component materials are charged to research and development expense when the inventory ownership transfers to the Company.

The Company analyzes inventory levels to identify inventory that may expire prior to sale, inventory that has a cost basis in excess of its net realizable value, or inventory in excess of expected sales requirements. Although the manufacturing of the r-SNM System is subject to strict quality control, certain batches or units of product may no longer meet quality specifications or may expire, which would require adjustments to the Company’s inventory values. The Company also applies judgment related to the results of quality tests that are performed throughout the production process, as well as the understanding of regulatory guidelines, to determine if it is probable that

inventory will be saleable. These quality tests are performed throughout the pre- and post-production processes, and the Company continually gathers information regarding product quality for periods after the manufacturing date. The r-SNM System currently has a maximum estimated shelf life range of 12 to 36 months and, based on sales forecasts, the Company expects to realize the carrying value of the product inventory. In the future, reduced demand, quality issues, or excess supply beyond those anticipated by management may result in a material adjustment to inventory levels, which would be recorded as an increase to cost of sales.

The determination of whether or not inventory costs will be realizable requires estimates by the Company’s management. A critical input in this determination is future expected inventory requirements based on internal sales forecasts. Management then compares these requirements to the expiry dates of inventory on hand. To the extent that inventory is expected to expire prior to being sold, management will write down the value of inventory.

As of December 31, 2020, the Company had $42.1 million, $3.5 million, and $17.5 million of finished goods inventory, work-in-process inventory and raw materials inventory, respectively, on hand net of minimal reserves. As of December 31, 2019, the Company had $7.0 million, $1.5 million and $7.2 million of finished goods inventory, work-in-process inventory and raw materials inventory, respectively, on hand net of reserves of $0.1 million.

Customer and Vendor Concentration

As of December 31, 2020 and 2019, there were no customers who accounted for over 10% of the Company’s consolidated accounts receivable. As of December 31, 2020 and 2019, there was one and no vendor, respectively, who accounted for over 10% of the Company’s consolidated accounts payable.

Property and Equipment

Property and equipment are stated at cost less accumulated depreciation. Depreciation is computed using the straight-line method over the estimated useful lives of the assets, generally between three and seven years. Leasehold improvements are amortized over the lesser of the life of the lease or the useful life of the improvements. Maintenance and repairs are charged to expense as incurred. When assets are retired or otherwise disposed of, the cost and accumulated depreciation are removed from the balance sheet and any resulting gain or loss is reflected in operations.

Intangible Asset

The intangible asset represents exclusive rights to an additional field-of-use on the patent suite within the License Agreement with AMF. The additional field-of-use was provided in exchange for 50,000 shares of Series A preferred stock, the fair value of which was $1.0 million in 2013. The intangible asset was recorded at its fair value of $1.0 million at the date contributed. In connection with the IPO, such shares of Series A preferred stock were converted into common stock. Amortization of this asset is recorded over the shorter of the patent or legal life on a straight-line basis. The weighted-average amortization period is 8.71 years. The Company will review the intangible asset for impairment whenever an impairment indicator exists. There have been no intangible asset impairment charges to date.

Impairment of Long-Lived Assets

The Company reviews its long-lived assets for impairment whenever events or changes in circumstances indicate that the carrying amount of an asset may not be recoverable. Recoverability is measured by comparing the carrying amount to the future net cash flows that the assets are expected to generate. If said assets are considered to be impaired, the impairment that would be recognized is measured by the amount by which the carrying amount of the assets exceeds the projected discounted future net cash flows arising from the asset. There have been no such impairments of long-lived assets to date.

Leases

In accordance with ASU No. 2016-02, “Leases (Topic 842)”, components of a lease should be split into three categories: lease components, non-lease components, and non-components. The fixed and in-substance fixed contract consideration (including any consideration related to non-components) must be allocated based on the respective relative fair values to the lease components and non-lease components. Entities may elect not to separate lease and non-lease components. Rather, entities would account for each lease component and related non-lease component together as a single lease component. The Company has elected to account for lease and non-lease components together as a single lease component for all underlying assets and allocate all of the contract consideration to the lease component only. Topic 842 allows for the use of judgment in determining whether the assumed lease term is for a major part of the remaining economic life of the underlying asset and whether the present value of lease payments represents substantially all of the fair value of the underlying asset. The Company applies the bright line thresholds referenced in Topic 842 to assist in evaluating leases for appropriate classification. The aforementioned bright lines are applied consistently to the Company’s entire portfolio of leases.

Operating lease ROU asset and operating lease liabilities are recognized based on the present value of the future minimum lease payments over the lease term at commencement date. As the Company’s lease does not provide an implicit rate, the Company uses its incremental borrowing rate, which is the rate for a fully collateralized amortizing loan with the same maturity as the lease term, based on the information available at commencement date in determining the present value of future payments. The operating lease ROU asset also includes any lease payments made and excludes lease incentives and initial direct costs incurred. The lease terms may include options to extend or terminate the lease when it is reasonably certain that the Company will exercise that option. Lease expense for minimum lease payments is recognized on a straight-line basis over the lease term.

Research and Development

Research and development costs are charged to operations as incurred. Research and development costs include salary and personnel-related costs, costs of clinical studies and testing, supplies and materials, and outside consultant costs.

Advertising Expense

The Company expenses advertising costs as they are incurred. During the years ended December 31, 2020, 2019, and 2018, advertising expense totaled $2.9 million, $2.6 million and $1.1 million, respectively, and are recorded within the sales and marketing expenses in its consolidated statements of comprehensive loss.

Income Taxes

The Company accounts for income taxes using the asset and liability method to compute the difference between the tax basis of assets and liabilities and the related financial amounts, using currently enacted tax rates. The Company has deferred tax assets. The realization of these deferred tax assets is dependent upon the Company’s ability to generate sufficient taxable income in future years. Valuation allowances are established, when necessary, to reduce deferred tax assets to the amount that more likely than not will be realized. The Company evaluates the recoverability of the deferred tax assets annually, and maintains a full valuation allowance on its deferred tax assets. The Company recognizes the tax benefit from an uncertain tax position only if it is more likely than not that the tax position will be sustained on examination by taxing authorities, based on the technical merits of the position. The Company is subject to transfer pricing and other tax regulations designed to ensure that appropriate levels of income are reported as earned by the Company’s U.S. and foreign entities and are taxed accordingly. In the normal course of business, the Company is audited by federal, state and foreign tax authorities, and subject to inquiries from those tax authorities regarding the amount of taxes due. These inquiries may relate to the timing and amount of deductions and the allocation of income among various tax jurisdictions. The Company’s policy is to recognize interest and penalties related to unrecognized tax benefits, if any, in income tax expense.

Stock-Based Compensation

The Company measures the cost of employee and non-employee services in exchange for an award of equity instruments based on the grant-date fair value of the award and recognizes compensation cost over the requisite service period (typically the vesting period), generally four years. Forfeitures are estimated at the time of the grant and revised in subsequent periods to reflect differences between the estimates and the number of shares that actually become exercisable. The Company uses the Black-Scholes option pricing model to determine the fair value of stock options (as of the date of grant) that have service conditions for vesting. Stock options and restricted shares awards vest based on service conditions, typically over four years.

The Company also grants shares of performance-based restricted stock units that typically vest after one year only if the Company has also achieved certain performance objectives as defined and approved by the Company’s board of directors. The fair value of performance awards are determined based on the Company’s stock price at the date of grant and expensed over the performance period based on the probability of achieving the performance objectives. In addition, the Company also grants market-based restricted stock units that have combined market conditions and service conditions for vesting, for which the Company uses the Monte Carlo valuation model to value equity awards (as of the date of grant).

Net Loss per Share of Common Stock

Basic net loss per share of common stock is calculated by dividing the net loss attributable to common stockholders by the weighted-average number of shares of common stock outstanding during the period, without consideration for potentially dilutive securities. Diluted net loss per share is computed by dividing the net loss attributable to common stockholders by the weighted-average number of shares of common stock and potentially dilutive securities outstanding for the period. For purposes of the diluted net loss per share calculation, convertible preferred stock, common and preferred stock warrants, common stock options, unvested RSAs and RSUs are considered to be potentially dilutive securities. Because the Company has reported a net loss in all periods presented, diluted net loss per share of common stock is the same as basic net loss per share of common stock for those periods.

For the years ended December 31, 2020, 2019, and 2018, there were 2,300,982, 1,737,430, and 9,192,127 potentially dilutive weighted-average shares, respectively, that were not included in the computation of diluted weighted-average shares of common stock and common stock equivalent shares outstanding because their effect would have been antidilutive given the Company’s net loss.

Recently Adopted Accounting Pronouncements

In August 2018, the FASB issued ASU No. 2018-15, “Intangibles—Goodwill and Other—Internal-Use Software (Subtopic 350-40): Customer’s Accounting for Implementation Costs Incurred in a Cloud Computing Arrangement That Is a Service Contract,” which aligns the requirements for capitalizing implementation costs incurred in a hosting arrangement that is a service contract with the requirements for capitalizing implementation costs incurred to develop or obtain internal-use software (and hosting arrangements that include an internal-use software license). This guidance is effective for annual periods beginning after December 15, 2019, which was the Company’s first quarter of fiscal year 2020. The adoption of this guidance did not have an impact on the Company’s consolidated financial statements or related disclosures.

In August 2018, the FASB issued ASU No. 2018-13, “Fair Value Measurement (Topic 820): Disclosure Framework—Changes to the Disclosure Requirements for Fair Value Measurement,” which modifies the disclosure requirements on fair value measurements and is intended to improve the effectiveness of disclosures, including the consideration of costs and benefits. This guidance is effective for annual periods beginning after December 15, 2019, which was the Company’s first quarter of fiscal year 2020, with early adoption permitted. The adoption of this guidance did not have an impact on the Company’s consolidated financial statements or related disclosures.

In June 2016, the FASB issued ASU No. 2016-13, “Financial Instruments—Credit Losses (Topic 326): Measurement of Credit Losses on Financial Instruments,” which updates the methodology used to measure current expected credit losses (CECL). This guidance applies to financial assets measured at amortized cost, including loans, held-to-maturity debt securities, net investments in leases, and trade accounts receivable as well as certain off-balance sheet credit exposures, such as loan commitments. This guidance replaces the current incurred loss impairment methodology with a methodology to reflect CECL and requires consideration of a broader range of

reasonable and supportable information to explain credit loss estimates. The guidance must be adopted using a modified retrospective transition method through a cumulative-effect adjustment to retained earnings (deficit) in the period of adoption. This guidance is effective for the Company as of January 1, 2020. The adoption of this guidance did not have an impact on the Company’s consolidated financial statements or related disclosures

Recent Accounting Pronouncements

In December 2019, the FASB issued ASU 2019-12, “Income Taxes—Simplifying the Accounting for Income Taxes,” which simplifies the accounting for income taxes by clarifying and amending existing guidance related to the recognition of franchise tax, the evaluation of a step-up in the tax basis of goodwill and the effects of enacted changes in tax laws or rates in the effective tax rate computation, among other clarifications. This guidance is effective for annual periods beginning after December 15, 2020, which is the Company’s first quarter of fiscal year 2021, with early adoption permitted. The adoption of this guidance is not expected to have an impact on the Company’s consolidated financial statements or related disclosures.

Commitments and Contingencies - Narrative (Details)		1 Months Ended	12 Months Ended
Commitments and Contingencies - Narrative (Details)	Mar. 16, 2020 petition	Oct. 31, 2013	Dec. 31, 2020 USD ($)	Dec. 31, 2019 USD ($)	Dec. 31, 2018 USD ($)	Aug. 31, 2020 ft²	Jun. 30, 2019 ft²	Nov. 30, 2017 ft²	Aug. 31, 2014 ft²
Loss Contingencies [Line Items]
Right-of-use assets obtained in exchange for operating lease liabilities			$ 3,800,000	$ 1,500,000	$ 3,300,000
Right-of-use asset			7,100,000	4,200,000
Operating lease payments			1,500,000	900,000	500,000
Operating lease ROU asset amortization			$ 900,000	$ 400,000	200,000
Weighted-average remaining lease term for operating leases			6 years 7 months 6 days	7 years 9 months 18 days
Discount rate on operating lease (as a percent)			6.70%	7.25%
Period after first sale royalty is due		12 years
Net revenue due as royalty (as a percent)		4.00%
Revenues			$ 111,535,000	$ 13,820,000	707,000
Royalty expense			4,400,000	600,000	$ 100,000
Accrued royalty			$ 1,400,000	$ 400,000
Operating Lease, Right-of-Use Asset, Statement of Financial Position [Extensible List]			us-gaap:OtherAssetsNoncurrent	us-gaap:OtherAssetsNoncurrent
Medtronic Litigation
Loss Contingencies [Line Items]
Number of petitions filed with the United States Patent and Trademark Office \| petition	7
Number of petitions accepted by the United States Patent and Trademark Office \| petition	6
Minimum number of claims by Medtronic that are invalid as determined by the United States Patent and Trademark Office \| petition	1
Maximum
Loss Contingencies [Line Items]
Royalty commitments			$ 200,000
First Lease
Loss Contingencies [Line Items]
Term of operating lease contract									5 years
Net rentable area (square feet) \| ft²									12,215
Second Lease
Loss Contingencies [Line Items]
Term of operating lease contract								7 years
Net rentable area (square feet) \| ft²								25,548
Operating lease renewal term of contract								5 years
Third Lease
Loss Contingencies [Line Items]
Term of operating lease contract							8 years
Net rentable area (square feet) \| ft²							32,621
Operating lease renewal term of contract							5 years
Fourth Lease
Loss Contingencies [Line Items]
Term of operating lease contract						38 months
Net rentable area (square feet) \| ft²						5,693

Subsequent Events (Details) - USD ($)	1 Months Ended
Subsequent Events (Details) - USD ($)	Feb. 28, 2021	Dec. 31, 2020	Dec. 31, 2019
Subsequent Event [Line Items]
Unamortized debt issuance costs		$ 390,000	$ 1,164,000
Face amount of debt instrument		$ 20,000,000	$ 20,000,000
Subsequent Event \| Term Loan due 2024 \| Term Loans
Subsequent Event [Line Items]
Face amount of debt instrument	$ 75,000,000
Stated interest rate (as a percent)	9.00%
Final payment fee (as a percent)	6.00%
Subsequent Event \| Term Loan due 2024 \| Term Loans \| Prime Rate
Subsequent Event [Line Items]
Basis spread on variable rate (as a percent)	5.75%
Subsequent Event \| Contura
Subsequent Event [Line Items]
Total consideration for acquisition	$ 200,000,000
Potential future milestone payment as part of acquisition	35,000,000
Upfront consideration paid in cash	$ 141,300,000
Upfront consideration, stock transferred as part of acquisition (shares)	1,096,583

Nature of Operations and Summary of Significant Accounting Policies - Revenue by Geographic Market (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Disaggregation of Revenue [Line Items]
Net revenue	$ 111,535	$ 13,820	$ 707
United States
Disaggregation of Revenue [Line Items]
Net revenue	107,542	8,376	0
International markets
Disaggregation of Revenue [Line Items]
Net revenue	$ 3,993	$ 5,444	$ 707

- Definition

Amount, excluding tax collected from customer, of revenue from satisfaction of performance obligation by transferring promised good or service to customer. Tax collected from customer is tax assessed by governmental authority that is both imposed on and concurrent with specific revenue-producing transaction, including, but not limited to, sales, use, value added and excise.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 280
-SubTopic 10
-Section 50
-Paragraph 30
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=120311839&loc=d3e8906-108599

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 280
-SubTopic 10
-Section 50
-Paragraph 40
-URI http://asc.fasb.org/extlink&oid=120311839&loc=d3e9031-108599

Reference 3: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 280
-SubTopic 10
-Section 50
-Paragraph 41
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=120311839&loc=d3e9038-108599

Reference 4: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 280
-SubTopic 10
-Section 50
-Paragraph 32
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=120311839&loc=d3e8933-108599

Reference 5: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 280
-SubTopic 10
-Section 50
-Paragraph 32
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=120311839&loc=d3e8933-108599

Reference 6: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 606
-SubTopic 10
-Section 50
-Paragraph 4
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=121604090&loc=SL49130543-203045

Reference 7: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 280
-SubTopic 10
-Section 50
-Paragraph 22
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=120311839&loc=d3e8736-108599

Reference 8: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 280
-SubTopic 10
-Section 50
-Paragraph 22
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=120311839&loc=d3e8736-108599

Reference 9: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 280
-SubTopic 10
-Section 50
-Paragraph 42
-URI http://asc.fasb.org/extlink&oid=120311839&loc=d3e9054-108599

Reference 10: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 606
-SubTopic 10
-Section 50
-Paragraph 5
-URI http://asc.fasb.org/extlink&oid=121604090&loc=SL49130545-203045

Reference 11: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 924
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SAB Topic 11.L)
-URI http://asc.fasb.org/extlink&oid=6472922&loc=d3e499488-122856

+ Details

Intangible Asset

12 Months Ended

Dec. 31, 2020

Goodwill and Intangible Assets Disclosure [Abstract]

Intangible Asset

The intangible asset represents exclusive rights to an additional field-of-use on the patent suite within the License Agreement with AMF. The intangible asset was recorded at its fair value of $1.0 million at the date contributed in 2013, which is the gross carrying amount of the intangible asset at December 31, 2020 and 2019. Accumulated amortization of the intangible asset is $0.8 million and $0.7 million at December 31, 2020 and 2019, respectively. The Company recorded expense for the amortization of intangible assets of $0.1 million during the years ended December 31, 2020, 2019, and 2018. The estimated future amortization expense as of December 31, 2020, is as follows (in thousands):


2021	$	115
2022	81
	$	196

Stockholders' Equity - Preferred Stock Narrative (Details) - $ / shares			12 Months Ended
	Nov. 02, 2018	Oct. 31, 2018	Dec. 31, 2018	Dec. 31, 2020	Dec. 31, 2019	Nov. 30, 2018	Oct. 30, 2018
Conversion of Stock [Line Items]
Preferred stock outstanding (shares)				0	0		12,219,315
Preferred stock authorized (shares)				10,000,000	10,000,000	10,000,000
Preferred stock, par value (USD per share)				$ 0.0001	$ 0.0001
Common Stock
Conversion of Stock [Line Items]
Stock issued upon conversion of preferred stock (shares)	15,813,297	15,813,297	15,813,297