Consolidated Balance Sheets - USD ($) $ in Thousands	Jun. 30, 2019	Dec. 31, 2018
Current assets
Cash and cash equivalents	$ 4,614	$ 13,766
Accounts receivable, net of allowances of $0 and $0, respectively	2,524	476
Costs and estimated earnings in excess of billings on uncompleted contracts	0	987
Inventory	54	1,109
Other current assets	951	1,311
Total current assets	8,143	17,649
Property and equipment, net	2,263	2,993
Operating lease right-of-use asset	1,477	0
Restricted cash	435	435
Intangible assets	428	486
Other assets	1,494	1,470
Total assets	14,240	23,033
Current liabilities
Accounts payable	1,705	2,411
Accrued liabilities	4,816	5,602
Billings on uncompleted contracts in excess of related costs	101	0
Other current liabilities	10,042	10,154
Current portion of operating lease liability	646	0
Current portion of finance lease obligations	23	21
Total current liabilities	17,333	18,188
Operating lease liability, net of current portion	1,615	0
Finance lease obligations, net of current portion	22	33
Deferred rent, net of current portion	0	695
Total liabilities	18,970	18,916
Commitments and contingencies (Note 10)
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; 150,000 shares authorized; 110,223 and 100,105 shares issued and outstanding at June 30, 2019 and December 31, 2018, respectively	110	100
Additional paid-in capital	558,334	550,133
Accumulated deficit	(563,174)	(546,116)
Total shareholders' equity (deficit)	(4,730)	4,117
Total liabilities and shareholders' equity (deficit)	14,240	23,033
Reconciliation of cash, cash equivalents, and restricted cash balances
Cash and cash equivalents	4,614	13,766
Restricted cash	435	435
Cash, cash equivalents, and restricted cash	$ 5,049	$ 14,201