Consolidated Balance Sheets - USD ($) $ in Thousands	Jun. 30, 2017	Dec. 31, 2016
Current assets
Cash and cash equivalents	$ 17,744	$ 15,139
Accounts receivable, net of allowances of $26 and $26, respectively	805	245
Inventory	2,677	1,233
Other current assets	4,233	731
Total current assets	25,459	17,348
Property and equipment, net	3,299	1,537
Restricted cash	435	435
Intangible assets	660	718
Other assets	58	68
Total assets	29,911	20,106
Current liabilities
Accounts payable	1,852	2,195
Accrued liabilities	4,706	3,704
Deferred revenue	999	999
Billings on uncompleted contracts in excess of related costs	3,667	168
Other current liabilities	10,070	178
Total current liabilities	21,294	7,244
Deferred revenue, net of current portion	4,654	5,150
Deferred rent, net of current portion	102	185
Other long-term liabilities	36	53
Total liabilities	26,086	12,632
Commitments and contingencies (Note 7)
Shareholders' equity
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; 71,596 and 68,093 shares issued and outstanding	72	68
Additional paid-in capital	514,737	507,249
Accumulated deficit	(510,984)	(499,843)
Total shareholders' equity	3,825	7,474
Total liabilities and shareholders' equity	$ 29,911	$ 20,106