Risks and Uncertainties (Details) - USD ($) $ in Thousands	6 Months Ended		31 Months Ended
	Jun. 30, 2023	Jun. 30, 2022	Jun. 30, 2023	Dec. 31, 2022	Jul. 15, 2019
Concentration Risk [Line Items]
Cash and cash equivalents	$ 22,436		$ 22,436	$ 27,273
Accumulated deficit	(308,931)		$ (308,931)	$ (311,207)
At-the-market offering
Concentration Risk [Line Items]
Number of shares issued in transaction (in shares)			13,402,516
Consideration received on sale of stock			$ 44,796
Payments for stock issuance costs	312	$ 139	2,395
Remaining amount available for offering	$ 28,014		$ 28,014
Equity distribution agreement
Concentration Risk [Line Items]
Number of shares issued in transaction (in shares)	3,060,559	1,404,878
Consideration received on sale of stock	$ 5,090	$ 2,473
Senior secured notes due 2025
Concentration Risk [Line Items]
Interest rate					12.50%