Consolidated Statements of Stockholders' Equity - USD ($) shares in Thousands, $ in Thousands	Common Stock	Treasury Shares/Stock	Additional Paid-in Capital	Accumulated Deficit	Accumulated Other Comprehensive Income	Total
Beginning balance (in shares) at Dec. 31, 2019	94,972	(121)
Beginning balance at Dec. 31, 2019	$ 9	$ (441)	$ 374,525	$ (286,066)	$ 410	$ 88,437
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net loss				(5,942)		(5,942)
Other comprehensive income (loss)					498	498
Stock-based compensation			1,066			1,066
Issuance of common stock, RSUs (in shares)	178
Issuance of common stock, RSUs	$ 1		(1)
Proceeds from the exercise of stock options and ESPP (in shares)	112
Proceeds from the exercise of stock options and ESPP			76			76
Ending balance (in shares) at Mar. 31, 2020	95,262	(121)
Ending balance at Mar. 31, 2020	$ 10	$ (441)	375,666	(292,008)	908	84,135
Beginning balance (in shares) at Dec. 31, 2019	94,972	(121)
Beginning balance at Dec. 31, 2019	$ 9	$ (441)	374,525	(286,066)	410	88,437
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net loss						(16,877)
Other comprehensive income (loss)						53
Ending balance (in shares) at Sep. 30, 2020	96,684	(121)
Ending balance at Sep. 30, 2020	$ 10	$ (441)	378,309	(302,943)	463	75,398
Beginning balance (in shares) at Mar. 31, 2020	95,262	(121)
Beginning balance at Mar. 31, 2020	$ 10	$ (441)	375,666	(292,008)	908	84,135
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net loss				(5,357)		(5,357)
Other comprehensive income (loss)					(547)	(547)
Stock-based compensation			1,278			1,278
Issuance of common stock, RSUs (in shares)	438
Ending balance (in shares) at Jun. 30, 2020	95,700	(121)
Ending balance at Jun. 30, 2020	$ 10	$ (441)	376,944	(297,365)	361	79,509
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net loss				(5,578)		(5,578)
Other comprehensive income (loss)					102	102
Stock-based compensation			1,282			1,282
Issuance of common stock, RSUs (in shares)	877
Proceeds from the exercise of stock options and ESPP (in shares)	107
Proceeds from the exercise of stock options and ESPP			83			83
Ending balance (in shares) at Sep. 30, 2020	96,684	(121)
Ending balance at Sep. 30, 2020	$ 10	$ (441)	378,309	(302,943)	463	75,398
Beginning balance (in shares) at Dec. 31, 2020	97,248	(121)
Beginning balance at Dec. 31, 2020	$ 10	$ (441)	379,696	(304,607)	618	75,276
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net loss				(8,835)		(8,835)
Other comprehensive income (loss)					325	325
Stock-based compensation			2,486			2,486
Issuance of common stock, RSUs (in shares)	73
Proceeds from the exercise of stock options and ESPP (in shares)	149
Proceeds from the exercise of stock options and ESPP			132			132
Ending balance (in shares) at Mar. 31, 2021	97,470	(121)
Ending balance at Mar. 31, 2021	$ 10	$ (441)	382,314	(313,442)	943	69,384
Beginning balance (in shares) at Dec. 31, 2020	97,248	(121)
Beginning balance at Dec. 31, 2020	$ 10	$ (441)	379,696	(304,607)	618	75,276
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net loss						(17,317)
Other comprehensive income (loss)						273
Ending balance (in shares) at Sep. 30, 2021	99,162	(121)
Ending balance at Sep. 30, 2021	$ 10	$ (441)	384,337	(321,924)	891	62,873
Beginning balance (in shares) at Mar. 31, 2021	97,470	(121)
Beginning balance at Mar. 31, 2021	$ 10	$ (441)	382,314	(313,442)	943	69,384
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net loss				(5,091)		(5,091)
Other comprehensive income (loss)					31	31
Stock-based compensation			1,085			1,085
Issuance of common stock, RSUs (in shares)	485
Proceeds from the exercise of stock options and ESPP (in shares)	4
Proceeds from the exercise of stock options and ESPP			4			4
Ending balance (in shares) at Jun. 30, 2021	97,959	(121)
Ending balance at Jun. 30, 2021	$ 10	$ (441)	383,403	(318,533)	974	65,413
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net loss				(3,391)		(3,391)
Other comprehensive income (loss)					(83)	(83)
Stock-based compensation			1,109			1,109
Issuance of common stock, RSUs (in shares)	1,200
Proceeds from the exercise of stock options and ESPP (in shares)	3
Proceeds from the exercise of stock options and ESPP			3			3
Net cash paid for payroll taxes on RSU releases			(178)			(178)
Ending balance (in shares) at Sep. 30, 2021	99,162	(121)
Ending balance at Sep. 30, 2021	$ 10	$ (441)	$ 384,337	$ (321,924)	$ 891	$ 62,873