Consolidated Balance Sheets - USD ($) $ in Thousands	Sep. 30, 2017	Dec. 31, 2016
Current assets
Cash and cash equivalents	$ 25,303	$ 15,139
Accounts receivable, net of allowances of $26 and $26, respectively	240	245
Inventory	4,253	1,233
Other current assets	3,192	731
Total current assets	32,988	17,348
Property and equipment, net	3,200	1,537
Restricted cash	435	435
Intangible assets	631	718
Other assets	50	68
Total assets	37,304	20,106
Current liabilities
Accounts payable	3,858	2,195
Accrued liabilities	3,995	3,704
Deferred revenue	999	999
Billings on uncompleted contracts in excess of related costs	1,453	168
Other current liabilities	10,034	178
Total current liabilities	20,339	7,244
Deferred revenue, net of current portion	4,402	5,150
Deferred rent, net of current portion	59	185
Other long-term liabilities	27	53
Total liabilities	24,827	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; 78,594 and 68,093 shares issued and outstanding	79	68
Additional paid-in capital	528,623	507,249
Accumulated deficit	(516,225)	(499,843)
Total shareholders' equity	12,477	7,474
Total liabilities and shareholders' equity	$ 37,304	$ 20,106