CONDENSED CONSOLIDATED STATEMENTS OF STOCKHOLDERS' EQUITY - USD ($) $ in Thousands	Common Stock	Additional Paid-in Capital	Accumulated Other Comprehensive Loss	Accumulated Deficit	Total
Balance at beginning of period at Dec. 31, 2020		$ 542,286	$ (94)	$ (504,542)	$ 37,650
Balance at beginning of period (in shares) at Dec. 31, 2020	45,109,314
Increase (Decrease) in Stockholders' Equity
Issuance of common stock in connection with exercise of stock options and vesting of restricted stock units		(2,579)			(2,579)
Issuance of common stock in connection with exercise of stock options and warrants and vesting of restricted stock units (in shares)	666,144
Issuance of common stock in connection with public offering, net of offering costs of $7,011		103,348			103,348
Issuance of common stock in connection with public offering, net of offering costs of $7,011 (in shares)	6,306,271
Unrealized loss on marketable securities			(35)		(35)
Foreign currency translation adjustment			(11)		(11)
Stock-based compensation expense		2,675			2,675
Net loss				(28,754)	(28,754)
Balance at end of period at Mar. 31, 2021		645,730	(140)	(533,296)	112,294
Balance at end of period (in shares) at Mar. 31, 2021	52,081,729
Balance at beginning of period at Dec. 31, 2021	$ 1	792,971	(224)	(595,407)	$ 197,341
Balance at beginning of period (in shares) at Dec. 31, 2021	61,228,446				61,228,446
Increase (Decrease) in Stockholders' Equity
Issuance of common stock in connection with exercise of stock options and vesting of restricted stock units		49			$ 49
Issuance of common stock in connection with exercise of stock options and warrants and vesting of restricted stock units (in shares)	509,037
Unrealized loss on marketable securities			(748)		(748)
Stock-based compensation expense		2,346			2,346
Net loss				(18,789)	(18,789)
Balance at end of period at Mar. 31, 2022	$ 1	$ 795,366	$ (972)	$ (614,196)	$ 180,199
Balance at end of period (in shares) at Mar. 31, 2022	61,737,483				61,737,483