Balance Sheet Accounts - Prepaid Expenses and Other Current Assets (Details) - USD ($) $ in Thousands	Dec. 31, 2021	Dec. 31, 2020
Balance Sheet Related Disclosures [Abstract]
Advances to commercial manufacturers	$ 942	$ 660
Prepaid FDA user fee and advances to CROs	1,108	1,262
Prepaid insurance	196	191
Prepaid income taxes	1,173	0
Convertible promissory note, net	5,312	0
All other	3,159	1,605
Total Prepaid expenses and other current assets	$ 11,890	$ 3,718