Consolidated Balance Sheets - USD ($) $ in Thousands	Dec. 31, 2016	Dec. 31, 2015
Current assets
Cash and cash equivalents	$ 15,139	$ 7,888
Accounts receivable, net of allowances of $26 and $38, respectively	245	1,687
Inventory	1,233	862
Other current assets	731	638
Total current assets	17,348	11,075
Property and equipment, net	1,537	1,669
Restricted cash	435	435
Intangible assets	718	845
Other assets	68	18
Total assets	20,106	14,042
Current liabilities
Accounts payable	2,195	2,183
Accrued liabilities	3,882	3,399
Deferred revenue	999	2,122
Billings on uncompleted contracts in excess of related costs	168	0
Total current liabilities	7,244	7,704
Deferred revenue, net of current portion	5,150	6,149
Deferred rent, net of current portion	185	342
Other long-term liabilities	53	0
Total liabilities	12,632	14,195
Commitments and contingencies (Note 11)
Shareholders' equity (deficit)
Preferred stock, par value $0.001; 25,000 shares authorized; 0 and 0 shares issued and outstanding	0	0
Common stock, par value $0.001; 100,000 shares authorized; 68,093 and 47,423 shares issued and outstanding at December 31, 2016 and 2015, respectively	68	47
Additional paid-in capital	507,249	483,171
Accumulated deficit	(499,843)	(483,371)
Total shareholders' equity (deficit)	7,474	(153)
Total liabilities and shareholders' equity (deficit)	$ 20,106	$ 14,042