Consolidated Balance Sheets (USD $) In Thousands, unless otherwise specified	Mar. 31, 2015	Dec. 31, 2014
Current assets:
Cash and cash equivalents	$ 2,942	$ 2,156
Marketable securities	14,063	13,952
Inventory-work in process	480	0
Prepaid expenses and other current assets	432	399
Total current assets	17,917	16,507
Property and equipment, net	11,805	4,601
Patent and trademark rights, net	935	861
Construction in progress	0	7,337
Other assets	134	134
Total assets	30,791	29,440
Current liabilities:
Accounts payable	2,317	2,081
Accrued expenses	1,489	2,333
Current portion of capital lease	15	22
Total current liabilities	3,821	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 225,737,722 and 204,004,818, respectively	226	204
Additional paid-in capital	308,007	302,729
Accumulated other comprehensive loss	(49)	(160)
Accumulated deficit	(281,214)	(277,769)
Total stockholders’ equity	26,970	25,004
Total liabilities and stockholders’ equity	$ 30,791	$ 29,440