Stockholders' Equity - Stock Options and Warrants (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended	9 Months Ended
	Mar. 31, 2021	Sep. 30, 2021	Dec. 31, 2020
Warrants, Number of Shares [Roll Forward]
Warrants, Outstanding, Beginning of Period (in shares)	2,638,355	2,638,355
Warrants, Granted (in shares)		19,519,393
Warrants, Exercised (in shares)		(801,148)
Warrants, Forfeited (in shares)		0
Warrants, Expired (in shares)		0
Warrants, Outstanding, End of Period (in shares)		21,356,600
Warrants Weighted Average Exercise Price [Roll Forward]
Warrants Outstanding, Beginning of Period (in dollars per share)	$ 2.18	$ 2.18
Warrants, Granted (in dollars per share)		2.90
Warrants, Exercised (in dollars per share)		2.19
Warrants, Forfeited (in dollars per share)		0
Warrants, Expired (in dollars per share)		0
Warrants Outstanding, End of Period (in dollars per share)		$ 2.84
Warrants, Outstanding, Weighted Average Remaining Contractual Term	4 years 11 months 23 days	4 years 7 months 17 days
Warrants Outstanding, Aggregate Intrinsic Value		$ 0	$ 0
Warrants, Vested and expected to vest (in shares)		21,356,600
Weighted Average Exercise Price, Warrants Vested And Expected To Vest		$ 2.84
Warrants, Vested and expected to vest, Weighted Average Remaining Contractual Term		4 years 7 months 17 days
Warrants, Vested and expected to vest, Aggregate Intrinsic Value		$ 0
Warrants, Vested (in shares)		21,356,600
Warrants, Vested, Weighted Average Exercise Price (in dollars per share)		$ 2.84
Warrants, Vested, Weighted Average Remaining Contractual Term		4 years 7 months 17 days
Warrants, Vested, Aggregate Intrinsic Value		$ 0
US Equity Plan [Member]
Options, Outstanding [Roll Forward]
Options, Outstanding, Beginning of Period (in shares)	963,700	963,700
Options, Granted (in shares)		1,314,790
Options, Exercised (in shares)		(7,250)
Options, Forfeited (in shares)		(19,492)
Options, Expired (in shares)		(109,549)
Options, Outstanding, End of Period (in shares)		2,142,199
Options, Outstanding, Weighted Average Exercise Price [Abstract]
Options, Outstanding. Beginning of Period (in dollars per share)	$ 14.64	$ 14.64
Options, Granted (in dollars per share)		1.32
Options, Exercised (in dollars per share)		3.28
Options, Forfeited (in dollars per share)		1.92
Options, Expired (in dollars per share)		34.12
Options, Outstanding, End of Period (in dollars per share)		$ 5.63
Options, Outstanding, Weighted Average Remaining Contractual Term	5 years 10 months 9 days	8 years 3 months 3 days
Options, Outstanding, Aggregate Intrinsic Value		$ 0	$ 0
Options, Vested and expected to vest (in shares)		2,126,167
Options, Vested and expected to vest, Weighted Average Exercise Price (in dollars per share)		$ 5.65
Options, Vested and expected to vest, Weighted Average Remaining Contractual Term		8 years 3 months 3 days
Options, Vested and expected to vest, Aggregate Intrinsic Value		$ 0
Options, Vested (in shares)		1,122,583
Options, Vested, Weighted Average Exercise Price (in dollars per share)		$ 9.26
Options, Vested, Weighted Average Remaining Contractual Term		7 years 14 days
Options, Vested, Aggregate Intrinsic Value		$ 0