Condensed Consolidated Statement of Stockholders' Equity (Deficit) - USD ($) $ in Thousands	Total	Common Stock [Member]	Additional Paid-in Capital [Member]	Accumulated Deficit [Member]	Accumulated Other Comprehensive Income (Loss) [Member]
Beginning balance at Dec. 31, 2020	$ 174,750	$ 91	$ 723,482	$ (548,776)	$ (47)
Beginning balance, shares at Dec. 31, 2020		91,459,239
Issuance of common stock upon exercise of stock options, value	372	$ 1	371
Issuance of common stock upon exercise of stock options, shares		104,184
Issuance of common stock upon vesting of RSUs, net of tax withholdings, shares		650
Issuance of common stock under ESPP, value	392		392
Issuance of common stock under ESPP, shares		24,191
Stock-based compensation expense	3,624		3,624
Unrealized gain (loss) on investments	32				32
Net income (loss)	(35,465)			(35,465)
Ending balance at Mar. 31, 2021	143,705	$ 92	727,869	(584,241)	(15)
Ending balance, shares at Mar. 31, 2021		91,588,264
Beginning balance at Dec. 31, 2021	$ 131,507	$ 92	745,829	(614,354)	(60)
Beginning balance, shares at Dec. 31, 2021	91,889,418	91,889,418
Issuance of common stock upon exercise of stock options, value	$ 257		257
Issuance of common stock upon exercise of stock options, shares	92,478	92,478
Issuance of common stock upon vesting of RSUs, net of tax withholdings, shares		69,195
Issuance of common stock under ESPP, value	$ 892		892
Issuance of common stock under ESPP, shares		159,214
Stock-based compensation expense	5,079		5,079
Unrealized gain (loss) on investments	155				(155)
Net income (loss)	(56,624)			(56,624)
Ending balance at Mar. 31, 2022	$ 80,956	$ 92	$ 752,057	$ (670,978)	$ (215)
Ending balance, shares at Mar. 31, 2022	92,210,305	92,210,305