Purchase Agreement and Offerings Purchase Agreement and Offerings - Summary ATM Offering and Firm Commitment Offering (Details) $ / shares in Units, $ in Thousands	12 Months Ended
	Dec. 31, 2019 USD ($) $ / shares shares
Class of Stock [Line Items]
Total shares of common stock sold (in shares) | shares	3,528,532
Average price per share (in dollars per share) | $ / shares	$ 7.37
Gross proceeds	$ 25,989
Commissions earned by Cantor	212
Commissions earned by Cantor	$ 25,777
Two Thousand Nineteen Sales Agreement
Class of Stock [Line Items]
Total shares of common stock sold (in shares) | shares	1,374,686
Average price per share (in dollars per share) | $ / shares	$ 5.23
Gross proceeds	$ 7,193
Commissions earned by Cantor	212
Commissions earned by Cantor	$ 6,981
Underwriting Agreement
Class of Stock [Line Items]
Average price per share (in dollars per share) | $ / shares	$ 8.73
Gross proceeds	$ 18,796
Commissions earned by Cantor	0
Commissions earned by Cantor	$ 18,796