Consolidated Balance Sheets (Parenthetical) - USD ($) $ in Thousands	Mar. 31, 2017	Dec. 31, 2016
Statement Of Financial Position [Abstract]
Allowances for doubtful accounts receivable	$ 80	$ 197
Reserves for excess and obsolete inventory	148	148
Related-party notes payable, discount & issuance costs	938	1,033
Notes payable, discount & issuance costs	$ 938	$ 1,033
Preferred stock, par value	$ 0.001	$ 0.001
Preferred stock, shares authorized	5,000,000	5,000,000
Preferred stock, shares issued	0	0
Preferred stock, shares outstanding	0	0
Common stock, par value	$ 0.001	$ 0.001
Common stock, shares authorized	100,000,000	100,000,000
Common stock, shares issued	12,116,156	12,297,954
Common stock, shares outstanding	12,116,156	12,297,954