Stockholders' Equity, Restricted Stock Units (Details) - Restricted Stock Units ("RSUs") [Member] - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended	12 Months Ended
	Mar. 31, 2017	Dec. 31, 2016
Restricted stock units, number of shares [Roll Forward]
Outstanding RSUs, beginning of period (in shares)	351,921
Awarded (in shares)	0
Released (in shares)	(12,868)
Forfeited (in shares)	(69,123)
Outstanding RSUs, end of period (in shares)	269,930	351,921
Restricted stock units, weighted average grant-date fair value [Roll forward]
Outstanding RSUs, beginning of period (in dollars per share)	$ 4.59
Awarded (in dollars per share)	0
Released (in dollars per share)	4.04
Forfeited (in dollars per share)	8.25
Outstanding RSUs, end of period (in dollars per share)	$ 3.68	$ 4.59
Restricted stock units, additional disclosures [Abstract]
Outstanding RSUs, weighted average remaining contractual term	9 months 11 days	1 year 22 days
Outstanding RSUs, aggregate intrinsic value	$ 592	$ 908
Compensation cost not yet recognized [Abstract]
Unrecognized compensation cost related to restricted stock units	$ 488
Weighted average period of recognition for unrecognized compensation cost	1 year 3 months 18 days