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Stockholders' Equity - Issuance of Common Stock and Warrants (Details) - USD ($) $ / shares in Units, $ in Thousands		1 Months Ended		3 Months Ended		6 Months Ended		12 Months Ended
	Nov. 25, 2019	Jun. 30, 2021	Jan. 31, 2020	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020	Dec. 31, 2020
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Warrants issued (in shares)						310,860	721,546
Exercise price of common stock (in dollars per share)		$ 3.59		$ 3.59		$ 3.59
Amount paid for clearing fees		$ 18	$ 231
Offering costs paid on the issuance of common stock and warrants				$ 469	$ 0	$ 469	$ 474	$ 510
Proceeds from sale of common stock and warrants		$ 4,500	$ 2,300
Percentage of gross proceeds used to make payments on note			10.00%
Gross proceeds			$ 275
Payments on the Iliad Note				0	300	0	526
Proceeds from issuance of warrants						$ 1,100
Warrants exercised (in shares)						156,446
Proceeds from the exercise of warrants				$ 0	$ 51	$ 527	$ 51
Iliad Note
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Percentage of gross proceeds used to make payments on note	10.00%
Payments on the Iliad Note			$ 226
Institutional investors
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Sale of common stock (in shares)		990,100	688,360
Sale of common stock (in dollars per share)		$ 5.05	$ 3.37	$ 5.05		$ 5.05
Warrants issued (in shares)			688,360			269,180	673,361
Exercise price of common stock (in dollars per share)		3.3700	$ 3.37	3.3700	$ 3.3700	$ 3.3700	$ 3.3700
Purchase price (in usd per share)			$ 0.625
Placement agent
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Warrants issued (in shares)			48,185			41,680	48,185
Exercise price of common stock (in dollars per share)		$ 4.9940	$ 4.99	$ 4.9940	$ 4.9940	$ 4.9940	$ 4.9940
Amount paid for placement agent commissions		$ 400	$ 193
Amount paid related to expenses for registered direct offering and concurrent private placement		$ 51	$ 50

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