Organization and Operations - Liquidity (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended	6 Months Ended
	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020	Dec. 31, 2020
Common Stock
Accumulated deficit		$ (438,447)		$ (260,897)
Cash and cash equivalents	$ 51,885	$ 139,520	$ 51,885	$ 24,930
Cowen
Common Stock
Percentage of commission paid to underwriter based on proceeds from common stock		3.00%
Jefferies
Common Stock
Remaining available under sales agreement		$ 25,000
Jefferies | ATM
Common Stock
Maximum aggregate value of common shares which can be issued under the agreement		25,000
Common Stock
Common Stock
Issuance of common stock for at-the-market offerings (in shares)	926,429		1,100,001
Common Stock | ATM
Common Stock
Issuance of common stock for at-the-market offerings (in shares)			1,100,001
Share price (in dollars per share)	$ 6.87		$ 6.87
Proceeds from public offering, net of issuance costs		$ 7,300