Stockholders' Equity - January 2020 Equity Offering (Details) - USD ($) $ / shares in Units, $ in Thousands		1 Months Ended		3 Months Ended	12 Months Ended
	Nov. 25, 2019	Jun. 30, 2021	Jan. 31, 2020	Dec. 31, 2021	Dec. 31, 2021	Dec. 31, 2020
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Amount paid for clearing fees			$ 231
Offering costs paid on the issuance of common stock and warrants					$ 969	$ 510
Percent proceeds to be paid to Lender			10.00%
Payments on the Iliad Note					$ 0	1,306
Warrants exercised (in shares)					237,892
Proceeds from the exercise of warrants					$ 801	$ 918
January 2020 Institutional Investor
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Sale of common stock (USD per share)			$ 3.37
Purchase price (in dollars per share)			$ 0.625
Securities called by warrants (in shares)			688,360
Exercise price of warrants (in dollars per share)			$ 3.37
January 2020 Equity Offering
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of warrants issued (in shares)				229,414	229,414	467,306
Amount paid for placement agent commissions			$ 193
Amount paid related to expenses for registered direct offering and concurrent private placement			50
Amount paid for clearing fees			231
Offering costs paid on the issuance of common stock and warrants					$ 510	$ 510
Exercise price of warrants (in dollars per share)				$ 3.67	$ 3.67	$ 3.51
Net proceeds from sale of common stock and warrants			2,300
Gross proceeds from equity issuance			275
Warrants exercised (in shares)						269,240
Proceeds from the exercise of warrants					$ 801	$ 918
Estimated proceeds from issuance of warrants					$ 841
January 2020 Equity Offering | Iliad Note
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Percent proceeds to be paid to Lender	10.00%
Payments on the Iliad Note			226
Investor Warrants
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of warrants issued (in shares)					187,734	425,626
Sale of common stock (USD per share)		$ 5.05
Amount paid for placement agent commissions		$ 400
Amount paid related to expenses for registered direct offering and concurrent private placement		51
Amount paid for clearing fees		19
Offering costs paid on the issuance of common stock and warrants					$ 470
Net proceeds from sale of common stock and warrants		$ 4,500
January 2020 Equity Offering, Private Placement
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of warrants issued (in shares)					41,680	41,680
Amount paid for placement agent commissions			193
Amount paid related to expenses for registered direct offering and concurrent private placement			$ 50
Securities called by warrants (in shares)			48,185
Exercise price of warrants (in dollars per share)			$ 4.9940