Stock-Based Compensation - Stock Option Activity Under Stock Option Plan (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended		6 Months Ended		12 Months Ended
	Jun. 30, 2022	Jun. 30, 2021	Jun. 30, 2022	Jun. 30, 2021	Dec. 31, 2021
Number of Shares
Beginning Balance			10,665,869
Granted	692,500	41,500	3,382,500	4,395,438
Cancelled			(3,961,735)
Ending Balance	10,086,635		10,086,635		10,665,869
Options exercisable, at end of period	2,955,111		2,955,111		4,410,312
Options available for future grant	15,780,200		15,780,200
Weighted Average Exercise Price
Beginning Balance			$ 2.87
Granted			0.71
Cancelled			3.33
Ending Balance	$ 1.97		1.97		$ 2.87
Options exercisable, at end of period	$ 3.28		$ 3.28		$ 3.85
Weighted Average Contractual Term (Years)
Outstanding, at end of period			8 years 11 months 12 days
Options exercisable, at end of period			7 years 10 months 13 days		7 years 6 months 10 days
Aggregate Intrinsic Value
Outstanding, at end of period	$ 1,611		$ 1,611
Options exercisable, at end of period	$ 89		$ 89		$ 0