Warrants - Narrative (Details) $ / shares in Units, $ in Thousands	1 Months Ended	3 Months Ended
	Jan. 31, 2018 Underwriter_Agreement $ / shares shares	Mar. 31, 2020 USD ($)	Mar. 31, 2019 USD ($)	Dec. 31, 2019 USD ($)	Jan. 01, 2018 USD ($)
Class of Stock [Line Items]
Change in fair value of warrants		$ 781	$ (5,787)
Warrant liability		1,705		$ 2,486
(Level 3) | Warrants
Class of Stock [Line Items]
Issuance of Warrants		1,705		2,486	$ 18,200
Change in fair value of warrants		800	$ (5,800)
Warrant liability		$ 1,700		$ 2,500
2018 Public Offering | Common Stock
Class of Stock [Line Items]
Number of underwriting agreements | Underwriter_Agreement	2
Number of shares issued in transaction (in shares) | shares	6,670,625
Par value (in dollars per share) | $ / shares	$ 0.001
Total | 2018 Public Offering
Class of Stock [Line Items]
Number of shares issued in transaction (in shares) | shares	3,335,313