Shelf Registration Statement and At-the-Market Offering - Additional Information (Details) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended	9 Months Ended
	Sep. 30, 2019 USD ($) shares	Sep. 30, 2019 USD ($) $ / shares shares
Registration Payment Arrangement [Line Items]
Issuance of common stock (in shares) | shares	0	570
Proceeds from sales		$ 1,504
Offering costs		$ 203
Weighted average sales price (in dollars per share) | $ / shares		$ 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	11,293	$ 11,293
JMP Securities [Member] | Maximum [Member]
Registration Payment Arrangement [Line Items]
Aggregate offering price	$ 13,000	$ 13,000