Shelf Registration and At-the-Market Offering - Additional Information (Details) - USD ($) $ / shares in Units, $ in Thousands				1 Months Ended		12 Months Ended
	Aug. 31, 2021	Jul. 15, 2021	Feb. 28, 2021	Jul. 31, 2021	Feb. 28, 2021	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019	Aug. 03, 2021
Registration Payment Arrangement [Line Items]
Aggregate offering price	$ 22,800	$ 40,000							$ 22,800
Issuance of common stock (in shares)					1,186,000		2,726,000	658,000
Proceeds from sales					$ 3,025	$ 41,642	$ 7,500	$ 1,643
Offering costs					$ 157	1,538	$ 463	$ 210
Weighted average sales price (in dollars per share)					$ 2.68		$ 2.92	$ 2.82
Remaining shares available under Initial Registration Statement		37,000
Additional shares under Initial Registration Statement		$ 3,000
Additional amounts available to be sold							$ 0
Maximum [Member]
Registration Payment Arrangement [Line Items]
Aggregate offering price						50,000			100,000
Offering costs	100,000
At-the-market Offering [Member]
Registration Payment Arrangement [Line Items]
Aggregate offering price	$ 50,000								50,000
2021 Equity Distribution Agreement [Member]
Registration Payment Arrangement [Line Items]
Issuance of common stock (in shares)			1,186,000	4,316,000			2,726,000	658,000
Proceeds from sales			$ 3,025	$ 38,800			$ 7,500	$ 1,643
Offering costs			$ 157	$ 1,200			$ 463	$ 210
Weighted average sales price (in dollars per share)			$ 2.68	$ 9.27			$ 2.92	$ 2.82
JMP Securities [Member]
Registration Payment Arrangement [Line Items]
Aggregate offering price				$ 40,000
JMP Securities [Member] | 2019 Equity Distribution Agreement [Member] | Maximum [Member]
Registration Payment Arrangement [Line Items]
Aggregate offering price						$ 13,000
Compensation percentage						5.00%
JMP Securities [Member] | 2021 Equity Distribution Agreement [Member]
Registration Payment Arrangement [Line Items]
Aggregate offering price									$ 50,000
Compensation percentage		3.00%
Net of securities fees				$ 1,200
JMP Securities [Member] | 2021 Equity Distribution Agreement [Member] | At-the-market Offering [Member] | Maximum [Member]
Registration Payment Arrangement [Line Items]
Aggregate offering price		$ 40,000