Consolidated Statements of Cash Flows - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Operating activities:
Net loss	$ (141,447)	$ (162,141)	$ (116,389)
Adjustments to reconcile net loss to net cash used in operating activities:
Depreciation and amortization	5,845	6,283	5,108
Gain on sale of available for sale securities	(49)	(7)	0
Net amortization of premiums on marketable securities	1,053	1,588	1,685
Amortization of debt discount and loan fees	2,554	2,206	1,529
Issuance of common stock in connection with professional services rendered	0	0	452
Warrant expense related to vesting of ADM Warrant	97	556	98
Debt conversion expense	0	1,766	0
Restructuring charges	2,622	2,900	0
Stock-based compensation expense	15,684	25,549	18,653
Loss from equity method investments	21,994	23,432	8,237
Revaluation of warrant liability	0	(688)	(147)
Revaluation of derivative liabilities	(1)	(8,056)	6,392
Changes in operating assets and liabilities:
Accounts receivable	(4,436)	(9,441)	(7,268)
Unbilled revenues	1,966	(1,901)	2,045
Inventories	3,315	(5,497)	(2,946)
Prepaid expenses and other current assets	(815)	(842)	(764)
Other assets	(42)	3,582	3,262
Accounts payable	739	3,575	(2,563)
Accrued liabilities	(3,010)	(2,107)	5,955
Deferred revenue	3,460	(1,075)	1,983
Other current and long-term liabilities	5,356	2,205	(112)
Net cash used in operating activities	(85,115)	(118,113)	(74,790)
Investing activities:
Purchases of property, plant and equipment	(1,579)	(7,208)	(10,217)
Proceeds received from the sale of equipment	114	0	0
Purchases of marketable securities	(24,146)	(195,987)	(133,601)
Proceeds from maturities of marketable securities	105,589	135,464	126,073
Proceeds from sales of marketable securities	31,196	6,541	10,890
Capital contributions in unconsolidated joint ventures	(22,344)	(32,550)	(12,431)
Capitalized interest related to unconsolidated joint venture	0	(620)	(1,055)
Restricted certificates of deposit	287	(731)	0
Net cash provided by (used in) investing activities	89,117	(95,091)	(20,341)
Financing activities:
Repayments under loan agreements	(6)	(10,433)	(14,917)
Proceeds from the issuance of senior subordinated convertible notes, net of discount	0	143,894	119,750
Proceeds from the issuance of common stock, net of repurchases	746	8,945	4,718
Proceeds from borrowings under loan agreements	0	0	10,369
Payment for loan costs and fees	0	(465)	(541)
Proceeds from issuance of common stock in a public offering, net of underwriting discounts and commission	0	59,209	0
Cash settlement of vested restricted stock units	(32)	(68)	0
Net cash provided by financing activities	708	201,082	119,379
Effect of exchange rate changes on cash and cash equivalents	(433)	(166)	(89)
Net increase (decrease) of cash and cash equivalents	4,277	(12,288)	24,159
Cash and cash equivalents-beginning of period	42,689	54,977	30,818
Cash and cash equivalents-end of period	46,966	42,689	54,977
Supplemental disclosures of cash flow information:
Interest paid in cash, net of capitalized interest	11,175	7,558	3,499
Supplemental disclosure of noncash investing and financing activities:
Purchase of property, plant and equipment in accounts payable and accrued liabilities	232	154	3,413
Capital contribution to unconsolidated joint venture settled with reduction of receivable	5,480	15,300	0
Stock Issued During Period, Value, Other	3,052	0	7,126
Common stock issued in connection with use and operation of the Clinton Facility (see Note 10)	0	0	7,125
Conversion of Senior Convertible Notes to common stock	0	2,461	40,616
Early conversion on Senior Convertible Notes settled in common stock	0	217	3,602
Conversion of Senior Convertible Notes pursuant to inducement settled in common stock	$ 0	$ 18,125	$ 0