Stockholders' Equity - Stock Options and Warrants (Details) - USD ($) $ / shares in Units, $ in Thousands	6 Months Ended	12 Months Ended
	Jun. 30, 2020	Dec. 31, 2019
Warrants, Number of Shares [Roll Forward]
Warrants, Outstanding, Beginning of Period (in shares)	30,000
Warrants, Granted (in shares)	2,123,508
Warrants, Exercised (in shares)	0
Warrants, Forfeited (in shares)	0
Warrants, Expired (in shares)	0
Warrants, Outstanding, End of Period (in shares)	2,153,508	30,000
Warrants Weighted Average Exercise Price [Roll Forward]
Warrants, Granted (in dollars per share)	$ 2.16
Warrants, Exercised (in dollars per share)	0
Warrants, Forfeited (in dollars per share)	0
Warrants, Expired (in dollars per share)	0
Warrants Outstanding, End of Period (in dollars per share)	$ 2.21	$ 5.89
Warrants, Outstanding, Weighted Average Remaining Contractual Term	5 years 3 months 29 days	3 years 2 months 8 days
Warrants Outstanding, Aggregate Intrinsic Value	$ 0	$ 0
Warrants, Vested and expected to vest (in shares)	2,153,508
Weighted Average Exercise Price, Warrants Vested And Expected To Vest	$ 2.21
Warrants, Vested and expected to vest, Weighted Average Remaining Contractual Term	5 years 3 months 29 days
Warrants, Vested and expected to vest, Aggregate Intrinsic Value	$ 0
Warrants, Vested (in shares)	2,153,508
Warrants, Vested, Weighted Average Exercise Price (in dollars per share)	$ 2.21
Warrants, Vested, Weighted Average Remaining Contractual Term	5 years 3 months 29 days
Warrants, Vested, Aggregate Intrinsic Value	$ 0
US Equity Plan [Member]
Options, Outstanding [Roll Forward]
Options, Outstanding, Beginning of Period (in shares)	1,044,417
Options, Granted (in shares)	245,776
Options, Exercised (in shares)	0
Options, Forfeited (in shares)	(5,400)
Options, Expired (in shares)	(123,584)
Options, Outstanding, End of Period (in shares)	1,161,209	1,044,417
Options, Outstanding, Weighted Average Exercise Price [Abstract]
Options, Outstanding. Beginning of Period (in dollars per share)	$ 18.31
Options, Granted (in dollars per share)	3.22
Options, Exercised (in dollars per share)	0
Options, Forfeited (in dollars per share)	3.28
Options, Expired (in dollars per share)	21.48
Options, Outstanding, End of Period (in dollars per share)	$ 14.85	$ 18.31
Options, Outstanding, Weighted Average Remaining Contractual Term	6 years 11 months 23 days	6 years 21 days
Options, Outstanding, Aggregate Intrinsic Value	$ 0	$ 0
Options, Vested and expected to vest (in shares)	1,131,822
Options, Vested and expected to vest, Weighted Average Exercise Price (in dollars per share)	$ 15.14
Options, Vested and expected to vest, Weighted Average Remaining Contractual Term	6 years 11 months 1 day
Options, Vested and expected to vest, Aggregate Intrinsic Value	$ 0
Options, Vested (in shares)	829,034
Options, Vested, Weighted Average Exercise Price (in dollars per share)	$ 19.25
Options, Vested, Weighted Average Remaining Contractual Term	6 years 2 months 1 day
Options, Vested, Aggregate Intrinsic Value	$ 0