Basis of Presentation and Summary of Significant Accounting Policies - Reconciliation of Basic and Diluted Loss per Share (Details) - USD ($) shares in Thousands, $ in Thousands	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Numerator:
Net loss	$ (2,390)	$ (4,522)
Denominator:
Basic weighted average common shares outstanding (in shares)	11,900	11,718
Potential common shares from equity awards and warrants (in shares)	0	0
Diluted weighted average shares (in shares)	11,900	11,718