Condensed Consolidated Balance Sheets (USD $) In Thousands, unless otherwise specified	Sep. 30, 2014	Dec. 31, 2013
Current assets:
Cash and cash equivalents	$ 60,305	$ 54,977
Marketable securities	189,876	112,544
Accounts receivable, net	7,614	10,452
Unbilled revenues	5,684	1,101
Inventories	15,408	9,836
Prepaid expenses and other current assets	3,807	2,907
Total current assets	282,694	191,817
Property, plant and equipment, net	38,034	40,089
Investment in unconsolidated joint venture	41,896	22,532
Other assets	1,692	4,267
Total assets	364,316	258,705
Current liabilities:
Accounts payable	9,631	7,949
Accrued liabilities	21,677	15,005
Current portion of long-term debt	22	65
Deferred revenue	1,912	2,275
Total current liabilities	33,242	25,294
Deferred revenue	300	0
Warrant liability	0	688
Long-term debt	0	10,374
Convertible debt, inclusive of derivative liabilities of $1,660 and $5,914 at September 30, 2014 and December 31, 2013, respectively; and net of unamortized debt discounts of $11,693 and $4,610 at September 30, 2014 and December 31, 2013, respectively.	201,100	83,083
Other liabilities	1,051	318
Total liabilities	235,693	119,757
Commitments and contingencies (Note 12)
Stockholders' equity:
Preferred stock, par value $0.001—5,000,000 shares authorized; 0 shares issued and outstanding	0	0
Common stock, par value $0.001—150,000,000 shares authorized; 79,289,677 and 68,744,534 shares issued and outstanding at September 30, 2014 and December 31, 2013, respectively	79	69
Additional paid-in capital	558,805	448,990
Accumulated other comprehensive loss	(6,669)	(3,794)
Accumulated deficit	(423,592)	(306,317)
Total stockholders’ equity	128,623	138,948
Total liabilities and stockholders’ equity	$ 364,316	$ 258,705