Shelf Registration Statement and At-the-Market Offering - Additional Information (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended		6 Months Ended		12 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019	Dec. 31, 2019
Registration Payment Arrangement [Line Items]
Issuance of common stock (in shares)	0	570	0	570
Proceeds from sales		$ 1,504		$ 1,504
Offering costs		$ 203		$ 203	$ 203
Weighted average sales price (in dollars per share)		$ 3.00		$ 3.00
Maximum [Member]
Registration Payment Arrangement [Line Items]
Aggregate offering price	$ 50,000		$ 50,000
Compensation percentage			5.00%
Common stock aggregate offering price available for issuance	11,147		$ 11,147
JMP Securities [Member] | Maximum [Member]
Registration Payment Arrangement [Line Items]
Aggregate offering price	$ 13,000		$ 13,000