Consolidated Balance Sheets - USD ($) $ in Thousands	Jun. 30, 2015	Dec. 31, 2014
Current assets:
Cash and cash equivalents	$ 1,842	$ 2,156
Marketable securities	13,872	13,952
Inventory-work in process	1,009	0
Prepaid expenses and other current assets	338	399
Total current assets	17,061	16,507
Property and equipment, net	11,720	4,601
Patent and trademark rights, net	951	861
Construction in progress	0	7,337
Other assets	134	134
Total assets	29,866	29,440
Current liabilities:
Accounts payable	1,598	2,081
Accrued expenses	1,497	2,333
Current portion of capital lease	7	22
Total current liabilities	$ 3,102	$ 4,436
Commitments and contingencies (Note 6)
Stockholders’ equity:
Preferred stock, par value $0.01 per share, authorized 5,000,000; issued and outstanding; none	$ 0	$ 0
Common stock, par value $0.001 per share, authorized 350,000,000 shares; issued and outstanding 245,483,480 and 204,004,818, respectively	245	204
Additional paid-in capital	312,764	302,729
Accumulated other comprehensive loss	(186)	(160)
Accumulated deficit	(286,059)	(277,769)
Total stockholders’ equity	26,764	25,004
Total liabilities and stockholders’ equity	$ 29,866	$ 29,440