Consolidated Statements of Cash Flows (USD $) In Thousands, unless otherwise specified	3 Months Ended		106 Months Ended
	Mar. 31, 2014	Mar. 31, 2013	Mar. 31, 2014
Operating Activities
Net loss	$ (11,972)	$ (18,370)	$ (270,838)
Adjustments to reconcile net loss to net cash used in operating activities:
(Gain) loss from change in fair value of warrant liabilities	(1,278)		4,769
(Gain) loss from change in fair value of embedded derivative	(1,264)	1,330	(21,378)
Non-cash stock-based compensation	865	1,087	31,301
Depreciation and amortization	826	849	17,824
Non-cash interest expense	777	1,898	10,784
Loss on conversion of debt		926	2,038
Loss (gain) from change in fair value of derivatives		257	(605)
Other non-cash expenses			1,855
Changes in operating assets and liabilities (net of effects of acquisitions):
Accounts receivable	(306)	(338)	335
Inventories	(142)	2,227	(1,083)
Prepaid expenses and other current assets	35	(197)	347
Deposits and other assets	(31)		(318)
Accounts payable, accrued expenses, and long-term liabilities	(496)	1,325	7,509
Net cash used in operating activities	(12,986)	(9,006)	(217,460)
Investing Activities
Acquisitions of property, plant and equipment	(2,869)	(1,997)	(81,362)
Proceeds from sales tax refund			2,006
Other			(575)
Acquisition of Agri-Energy, net of cash assumed			(24,936)
Restricted certificate of deposit			(39)
Net cash used in investing activities	(2,869)	(1,997)	(104,906)
Financing Activities
Payments on secured debt	(250)	(1,639)	(33,475)
Debt and equity offering costs	(100)		(15,314)
Proceeds from issuance of common stock upon exercise of stock options and ESPP	2		1,381
Proceeds from issuance of common stock and common stock units			205,340
Proceeds from issuance of convertible preferred stock			86,025
Proceeds from issuance of convertible debt, net			42,300
Proceeds from issuance of secured debt			41,578
Proceeds from issuance of convertible promissory notes with warrants			3,000
Deposit on secured debt and other			(639)
Proceeds from the exercise of warrants			592
Net cash (used in) provided by financing activities	(348)	(1,639)	330,788
Net (decrease) increase in cash and cash equivalents	(16,203)	(12,642)	8,422
Cash and cash equivalents
Beginning of period	24,625	66,744
Ending of period	8,422	54,102	8,422
Supplemental disclosures of cash and non-cash investing and financing transactions
Cash paid for interest, net of interest capitalized	198	454	14,119
Accrued offering costs	130		130
Non-cash purchase of property, plant and equipment	129	281	129
Conversion of convertible debt to common stock		6,665	12,784
Issuance of common stock for services		483	483
Issuance of common stock warrants			4,048
Modification of warrants			179
Conversion of preferred stock warrants to common stock warrants upon initial public offering and reclassification of related liability to additional paid-in-capital			2,063
Deemed dividend—amortization of beneficial conversion feature on Series D-1 preferred stock			3,872
Promissory notes and accrued interest converted to Series C preferred stock			3,043
Issuance of Series C preferred stock upon exercise of warrant (amount reclassified from liability to equity)			1,458
Issuance of Series D-1 preferred stock to ICM, Inc. in exchange for a credit against future services			1,000
Reclassified deferred offering costs to additional paid-in-capital upon initial public offering			4,296
Issued with Secured Long Term Debt
Supplemental disclosures of cash and non-cash investing and financing transactions
Warrants issued with secured debt			1,746
Issued with Convertible Promissory Notes
Supplemental disclosures of cash and non-cash investing and financing transactions
Warrants issued with secured debt			$ 505