Organization - Narrative (Details) - USD ($) $ / shares in Units, $ in Thousands		1 Months Ended	9 Months Ended
	Jul. 14, 2020	Jun. 30, 2020	Sep. 30, 2020	Sep. 30, 2019	Dec. 31, 2019
Subsidiary, Sale of Stock [Line Items]
Gross proceeds from issuance of common stock			$ 48,424	$ 0
Net proceeds from the issuance of long-term debt			10,000	$ 19,481
Cash, cash equivalents and short-term investments			81,600
Accumulated deficit			$ 263,469		$ 198,853
Security And Loan Agreement, Tranche Two | Line of Credit | 2019 Credit Facility
Subsidiary, Sale of Stock [Line Items]
Net proceeds from the issuance of long-term debt	$ 10,000
June Offering
Subsidiary, Sale of Stock [Line Items]
Number of shares sold in public offering (in shares)		13,800,000
Price of shares sold in public offering (in dollars per share)		$ 3.75
Gross proceeds from issuance of common stock		$ 51,800
Net proceeds from issuance of common stock		$ 48,400
Over-Allotment Option
Subsidiary, Sale of Stock [Line Items]
Number of shares sold in public offering (in shares)		1,800,000