Consolidated Balance Sheets (Unaudited) - USD ($) $ in Thousands	Sep. 30, 2016	Dec. 31, 2015
Current assets:
Cash and cash equivalents	$ 4,473	$ 2,115
Marketable securities	3,536	6,795
Inventory-work in process		1,326
Assets held for sale	764
Prepaid expenses and other current assets	559	335
Total current assets	9,332	10,571
Property and equipment, net	9,779	11,237
Patent and trademark rights, net	919	862
Other assets	1,546	134
Total assets	21,576	22,804
Current liabilities:
Accounts payable	1,011	1,213
Accrued expenses	1,420	1,219
Current portion of capital lease		1
Total current liabilities	2,431	2,433
Redeemable warrants	2,514
Commitments and contingencies (Note 6)
Stockholders' equity:
Preferred stock, par value $0.01 per share, authorized 5,000,000; issued and outstanding; none
Common stock, par value $0.001 per share, authorized 350,000,000 shares; issued and outstanding 24,105,569 and 20,629,957, respectively	24	21
Additional paid-in capital	315,864	313,446
Accumulated other comprehensive income (loss)	71	(97)
Accumulated deficit	(299,328)	(292,999)
Total stockholders' equity	16,631	20,371
Total liabilities and stockholders' equity	$ 21,576	$ 22,804