Consolidated Balance Sheets (USD $) In Thousands, unless otherwise specified	Dec. 31, 2012	Dec. 31, 2011
Current assets:
Cash and cash equivalents	$ 30,818	$ 28,780
Marketable securities	118,187	214,944
Accounts receivable	3,280	4,029
Unbilled revenues	3,150	3,889
Inventories	6,890	3,129
Prepaid expenses and other current assets	2,954	4,122
Total current assets	165,279	258,893
Property, plant and equipment, net	32,225	25,985
Investments in unconsolidated joint ventures	19,047
Other assets	473	346
Total assets	217,024	285,224
Current liabilities:
Accounts payable	7,552	11,525
Accrued liabilities	9,320	9,288
Current portion of long-term debt	7,331	5,289
Deferred revenue	292	3,014
Other current liabilities	443	96
Total current liabilities	24,938	29,212
Other liabilities	303	491
Warrant liability	835
Long-term debt	7,637	14,963
Total liabilities	33,713	44,666
Commitments and contingencies (Note 12)
Stockholders' equity:
Preferred stock, par value $0.001-5,000,000 shares authorized at December 31, 2012 and 2011; 0 shares issued and outstanding at December 31, 2012 and 2011
Common stock, par value $0.001-150,000,000 shares authorized at December 31, 2012 and 2011; 61,000,724 and 59,908,138 shares issued and outstanding at December 31, 2012 and 2011, respectively	61	60
Additional paid-in capital	373,577	348,083
Accumulated other comprehensive loss	(399)	(789)
Accumulated deficit	(189,928)	(106,796)
Total stockholders' equity	183,311	240,558
Total liabilities and stockholders' equity	$ 217,024	$ 285,224