Stockholders' Equity, Stock Option (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended	12 Months Ended
	Mar. 31, 2017	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Options outstanding, number of options (in shares)		732,190
$2.29 - $2.29 [Member]
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Exercise price range, lower range limit (in dollars per share)		$ 2.29
Exercise price range, upper range limit (in dollars per share)		$ 2.29
Options outstanding, number of options (in shares)		428,013
Options outstanding, weighted average remaining contractual life		9 years 9 months 29 days
Options outstanding, weighted average exercise price (in dollars per share)		$ 2.29
$2.51 - $2.51 [Member]
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Exercise price range, lower range limit (in dollars per share)		2.51
Exercise price range, upper range limit (in dollars per share)		$ 2.51
Options outstanding, number of options (in shares)		115,438
Options outstanding, weighted average remaining contractual life		8 years 1 month 17 days
Options outstanding, weighted average exercise price (in dollars per share)		$ 2.51
$2.52 - $5.10 [Member]
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Exercise price range, lower range limit (in dollars per share)		2.52
Exercise price range, upper range limit (in dollars per share)		$ 5.10
Options outstanding, number of options (in shares)		74,784
Options outstanding, weighted average remaining contractual life		7 years 8 months 1 day
Options outstanding, weighted average exercise price (in dollars per share)		$ 2.84
$6.30 - $11.73 [Member]
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Exercise price range, lower range limit (in dollars per share)		6.30
Exercise price range, upper range limit (in dollars per share)		$ 11.73
Options outstanding, number of options (in shares)		73,805
Options outstanding, weighted average remaining contractual life		2 years 1 month 17 days
Options outstanding, weighted average exercise price (in dollars per share)		$ 7.86
$12.48 - $15.33 [Member]
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Exercise price range, lower range limit (in dollars per share)		12.48
Exercise price range, upper range limit (in dollars per share)		$ 15.33
Options outstanding, number of options (in shares)		9,963
Options outstanding, weighted average remaining contractual life		3 years 3 months 4 days
Options outstanding, weighted average exercise price (in dollars per share)		$ 13.02
$15.51 - $18.39 [Member]
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Exercise price range, lower range limit (in dollars per share)		15.51
Exercise price range, upper range limit (in dollars per share)		$ 18.39
Options outstanding, number of options (in shares)		30,187
Options outstanding, weighted average remaining contractual life		2 years 5 months 16 days
Options outstanding, weighted average exercise price (in dollars per share)		$ 17.73
Stock Options [Member]
Outstanding options, number of shares [Roll Forward]
Outstanding options, beginning of period (in shares)	1,381,843	1,381,843	1,223,156
Granted (in shares)		430,500	663,431
Exercised (in shares)		0	(185)
Forfeited (in shares)		(1,080,153)	(504,559)
Outstanding options, end of period (in shares)		732,190	1,381,843	1,223,156
Options vested and expected to vest (in shares)		679,822
Exercisable (in shares)		231,039
Outstanding options, weighted average exercise price per share [Roll Forward]
Outstanding options, beginning of period (in dollars per share)	$ 14.85	$ 14.85	$ 8.22
Granted (in dollars per share)		2.29	2.51
Exercised (in dollars per share)		0	2.51
Forfeited (in dollars per share)		5.90	7.12
Outstanding options, end of period (in dollars per share)		3.72	$ 14.85	$ 8.22
Options vested and expected to vest (in dollars per share)		3.83
Exercisable (in dollars per share)		$ 6.72
Outstanding options, additional disclosures [Abstract]
Outstanding options, weighted average remaining contractual term		8 years 2 months 1 day	4 years 11 months 12 days	6 years 7 months 28 days
Options vested and expected to vest, weighted average remaining contractual term		8 years 22 days
Exercisable, weighted average remaining contractual term		5 years 1 month 24 days
Outstanding options, aggregate intrinsic value		$ 56	$ 50	$ 0
Options vested and expected to vest, aggregate intrinsic value		50
Exercisable, aggregate intrinsic value		3
Options exercised in period, aggregate intrinsic value		0	0
Fair value of options vested		32	$ 1,300
Compensation cost not yet recognized [Abstract]
Unrecognized compensation cost related to stock options		$ 798
Weighted average period of recognition for unrecognized compensation cost		2 years 7 months 24 days
Stock Options [Member] | Chief Financial Officer [Member]
Outstanding options, number of shares [Roll Forward]
Forfeited (in shares)	(50,000)
Compensation cost not yet recognized [Abstract]
Reversal of previously recorded stock based compensation expense	$ 58