Condensed Consolidated Statements of Stockholders' Equity - USD ($) $ in Thousands	Total	Common Stock [Member]	Additional Paid-In Capital [Member]	Note Receivable [Member]	Accumulated Other Comprehensive Income (Loss) [Member]	Accumulated Deficit [Member]
Beginning Balance at Dec. 31, 2020	$ 385,613	$ 69	$ 870,788	$ (16)	$ 114	$ (485,342)
Beginning Balance, shares at Dec. 31, 2020		69,452,466
Net loss	(29,711)					(29,711)
Unrealized loss on investments	(128)				(128)	0
Issuance of common stock under equity incentive and employee stock purchase plans	2,163	$ 1	2,162	0	0	0
Issuance of common stock under equity incentive and employee stock purchase plans, shares		370,987
Repurchased shares upon vesting of restricted stock units for tax withholdings	(5,013)	$ 0	(5,013)	0	0	0
Repurchased shares upon vesting of restricted stock units for tax withholdings, shares		(80,960)
Employee stock-based compensation	7,840	$ 0	7,840	0	0	0
Compensation expense related to options granted to consultants	240	0	240	0	0	0
Ending Balance at Mar. 31, 2021	361,004	$ 70	876,017	(16)	(14)	(515,053)
Ending Balance, shares at Mar. 31, 2021		69,742,493
Beginning Balance at Dec. 31, 2021	$ 286,120	$ 70	903,646	(16)	(483)	(617,097)
Beginning Balance, shares at Dec. 31, 2021	70,357,557	70,357,557
Net loss	$ (38,608)					(38,608)
Unrealized loss on investments	(1,372)				(1,372)
Issuance of common stock upon net exercise of warrant		66,833
Issuance of common stock under equity incentive and employee stock purchase plans	6,279	$ 1	6,278
Issuance of common stock under equity incentive and employee stock purchase plans, shares		803,567
Repurchased shares upon vesting of restricted stock units for tax withholdings	(3,126)		(3,126)
Repurchased shares upon vesting of restricted stock units for tax withholdings, shares		(85,855)
Employee stock-based compensation	9,182		9,182
Compensation expense related to options granted to consultants	244		244
Ending Balance at Mar. 31, 2022	$ 258,719	$ 71	$ 916,224	$ (16)	$ (1,855)	$ (655,705)
Ending Balance, shares at Mar. 31, 2022	71,142,102	71,142,102