Consolidated Balance Sheets (Unaudited) - USD ($) $ in Thousands	Mar. 31, 2018	Dec. 31, 2017
Current assets:
Cash and cash equivalents	$ 8,479	$ 11,645
Restricted cash equivalent	251	251
Accounts receivable, less allowance of $997 in 2018 and $802 in 2017	9,739	10,124
Inventory, net	13,401	12,298
Prepaid expenses and other current assets	1,714	1,732
Total current assets	33,584	36,050
Property, plant, and equipment, net	3,424	3,674
Goodwill	2,926	2,926
Other assets	450	334
Total assets	40,384	42,984
Current liabilities:
Accounts payable	5,785	5,109
Accrued liabilities	5,119	5,609
Customer deposits	41	27
Deferred revenue, current portion	2,187	2,625
Total current liabilities	13,132	13,370
Lines of credit	1,823
Deferred income taxes, net	106	104
Deferred revenue, long-term	8	11
Loan payable, long-term	111
Warranty accrual, long-term	124	70
Other liabilities, long-term	143	169
Total liabilities	15,447	13,724
Commitments, contingencies, and subsequent event (Notes 10 and 14)
Stockholders' equity:
Preferred stock, par value $0.001 per share; 1,000,000 shares authorized; 0 shares issued and outstanding as of March 31, 2018 and December 31, 2017, respectively
Common stock, par value $0.001 per share; 200,000,000 shares authorized, 102,380,238 and 102,339,682 shares issued and outstanding as of March 31, 2018 and December 31, 2017, respectively	102	102
Additional paid-in-capital	225,524	224,910
Accumulated other comprehensive loss	(492)	(576)
Accumulated deficit	(200,197)	(195,176)
Total stockholders' equity	24,937	29,260
Total liabilities and stockholders' equity	$ 40,384	$ 42,984