Condensed Consolidated Statements of Stockholders’ Equity - USD ($) $ in Thousands	Total	Previously Reported	Revision of Prior Period, Adjustment	Common Stock	Common Stock Previously Reported	Common Stock Revision of Prior Period, Adjustment	Treasury Stock	Treasury Stock Previously Reported	Treasury Stock Revision of Prior Period, Adjustment	Additional Paid-In Capital	Additional Paid-In Capital Previously Reported	Additional Paid-In Capital Revision of Prior Period, Adjustment	Accumulated Other Comprehensive Income (Loss)	Accumulated Other Comprehensive Income (Loss) Previously Reported	Accumulated Deficit	Accumulated Deficit Previously Reported
Beginning balance (in shares) at Dec. 31, 2020				114,266,515	73,481,228	40,785,287	0	113,220	(113,220)
Beginning balance at Dec. 31, 2020	$ 185,917	$ (16,199)	$ 202,116	$ 11	$ 735	$ (724)	$ 0	$ (352)	$ 352	$ 597,274	$ 394,786	$ 202,488	$ (2)	$ (2)	$ (411,366)	$ (411,366)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Issuance of Common Stock upon exercise of options (in shares)				411,789
Issuance of Common Stock upon exercise of options	877									877
Issuance of Common Stock for services (in shares)				162,737
Issuance of Common Stock for services	114									114
Stock-based compensation	3,140									3,140
Surrender of shares in cashless exercise (in shares)				(15,189)
Surrender of shares in cashless exercise	(56)									(56)
Net unrealized loss on available-for-sale securities	(6)												(6)
Foreign currency translation gain (loss)	1												1
Net loss	(9,484)														(9,484)
Ending balance (in shares) at Mar. 31, 2021				114,825,852			0
Ending balance at Mar. 31, 2021	180,503			$ 11			$ 0			601,349			(7)		(420,850)
Beginning balance (in shares) at Dec. 31, 2021				181,552,241			0
Beginning balance at Dec. 31, 2021	$ 612,024			$ 18			$ 0			1,110,991			(72)		(498,913)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Issuance of Common Stock upon exercise of options (in shares)	624,685			624,685
Issuance of Common Stock upon exercise of options	$ 1,242									1,242
Issuance of Common Stock for services	50									50
Stock-based compensation	8,627									8,627
Net unrealized loss on available-for-sale securities	(652)												(652)
Foreign currency translation gain (loss)	(3)												(3)
Net loss	(3,979)														(3,979)
Ending balance (in shares) at Mar. 31, 2022				182,176,926			0
Ending balance at Mar. 31, 2022	$ 617,309			$ 18			$ 0			$ 1,120,910			$ (727)		$ (502,892)