Condensed Consolidated Balance Sheets (USD $) In Thousands, unless otherwise specified	Jun. 30, 2014	Dec. 31, 2013
Current assets:
Cash and cash equivalents	$ 80,364	$ 54,977
Marketable securities	204,802	112,544
Accounts receivable, net	14,418	10,452
Unbilled revenues	3,607	1,101
Inventories	14,810	9,836
Prepaid expenses and other current assets	2,775	2,907
Total current assets	320,776	191,817
Property, plant and equipment, net	38,715	40,089
Investment in unconsolidated joint venture	42,641	22,532
Other assets	1,640	4,267
Total assets	403,772	258,705
Current liabilities:
Accounts payable	11,190	7,949
Accrued liabilities	16,670	15,005
Current portion of long-term debt	38	65
Deferred revenue	2,578	2,275
Total current liabilities	30,476	25,294
Deferred revenue	600	0
Warrant liability	0	688
Long-term debt	0	10,374
Convertible debt, inclusive of derivative liabilities of $7,866 and $5,914 at June 30, 2014 and December 31, 2013, respectively; and net of unamortized debt discounts of $12,257 and $4,610 at June 30, 2014 and December 31, 2013, respectively.	206,741	83,083
Other liabilities	218	318
Total liabilities	238,035	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; 78,640,286 and 68,744,534 shares issued and outstanding at June 30, 2014 and December 31, 2013, respectively	79	69
Additional paid-in capital	551,210	448,990
Accumulated other comprehensive loss	(1,637)	(3,794)
Accumulated deficit	(383,915)	(306,317)
Total stockholders' equity	165,737	138,948
Total liabilities and stockholders' equity	$ 403,772	$ 258,705