Consolidated Balance Sheets (USD $) In Thousands, unless otherwise specified	Jun. 30, 2012	Dec. 31, 2011
Current assets:
Cash and cash equivalents	$ 2,170	$ 3,103
Marketable securities- unrestricted	19,442	26,229
Marketable securities- restricted	7,343	1,026
Inventories	1,107	897
Prepaid expenses and other current assets	425	531
Total current assets	30,487	31,786
Property and equipment, net	5,325	5,276
Patent and trademark rights, net	886	863
Marketable securities - unrestricted	0	1,958
Marketable securities - restricted	0	2,075
Construction in progress	4,347	1,484
Other assets	65	71
Total assets	41,110	43,513
Current liabilities:
Accounts payable	1,805	1,681
Accrued expenses	1,168	1,644
Margin account loan	4,335	1,695
Current portion of capital lease	50	49
Total current liabilities	7,358	5,069
Long-term liabilities:
Long-term portion of capital lease	73	99
Redeemable warrants	144	380
Total liabilities	7,575	5,548
Commitments and contingencies
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 136,221,041 and 135,642,303, respectively	136	136
Additional paid-in capital	265,181	264,958
Accumulated other comprehensive gain (loss)	266	(389)
Accumulated deficit	(232,048)	(226,740)
Total stockholders' equity	33,535	37,965
Total liabilities and stockholders' equity	$ 41,110	$ 43,513