Consolidated Balance Sheets (USD $) In Thousands, unless otherwise specified	Sep. 30, 2014	Dec. 31, 2013
Current assets:
Cash and cash equivalents	$ 1,262	$ 803
Marketable securities	16,169	17,391
Prepaid expenses and other current assets	235	358
Total current assets	17,666	18,552
Property and equipment, net	4,716	5,053
Patent and trademark rights, net	853	1,080
Construction in progress	7,269	7,046
Other assets	134	136
Total assets	30,638	31,867
Current liabilities:
Accounts payable	2,447	1,271
Accrued expenses	1,781	1,228
Current portion of capital lease	29	33
Total current liabilities	4,257	2,532
Long-term liabilities
Long-term portion of capital lease	3	23
Redeemable warrants	13	14
Total liabilities	4,273	2,569
Commitments and contingencies (Notes 6, 8, 10)
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 193,708,424 and 168,660,370, respectively	194	168
Additional paid-in capital	299,598	289,563
Accumulated other comprehensive loss	(114)	(114)
Accumulated deficit	(273,313)	(260,319)
Total stockholders’ equity	26,365	29,298
Total liabilities and stockholders’ equity	$ 30,638	$ 31,867