Consolidated Statements of Cash Flows - USD ($)	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Operating Activities
Net loss	$ (37,228,000)	$ (36,194,000)	$ (41,145,000)
Adjustments to reconcile net loss to net cash used in operating activities:
(Gain) from the change in fair value of derivative warrant liability	(1,783,000)	(577,000)	(6,530,000)
(Gain) from the change in fair value of the embedded derivative to the 2022 Notes			(3,470,000)
Loss/(Gain) from the change in fair value of 2017 Notes	4,204,000	(3,895,000)	(648,000)
Loss/(Gain) on exchange or conversion of debt	763,000	(232,000)
Loss/(Gain) on extinguishment of warrant liability	918,000	(1,775,000)
Loss on issuance of equity	1,519,000	2,523,000
Stock-based compensation	886,000	2,647,000	2,860,000
Depreciation and amortization	6,747,000	6,573,000	4,880,000
Non-cash interest expense	3,977,000	3,772,000	7,860,000
Other non-cash expenses	(1,000)	(7,000)	66,000
Changes in operating assets and liabilities:
Accounts receivable	269,000	970,000	(1,003,000)
Inventories	29,000	805,000	(711,000)
Prepaid expenses and other current assets	(119,000)	1,000	431,000
Accounts payable, accrued expenses, and long-term liabilities	(697,000)	(2,771,000)	(1,580,000)
Net cash used in operating activities	(20,516,000)	(28,160,000)	(38,990,000)
Investing Activities
Acquisitions of property, plant and equipment	(5,938,000)	(1,464,000)	(4,894,000)
Restricted certificate of deposit			(2,611,000)
Proceeds from sales tax refund for property, plant and equipment		144,000
Net cash used in investing activities	(5,938,000)	(1,320,000)	(7,505,000)
Financing Activities
Payments on secured debt	(504,000)	(318,000)	(9,824,000)
Debt and equity offering costs	(3,144,000)	(3,519,000)	(5,873,000)
Proceeds from issuance of common stock upon exercise of stock options and employee stock purchase plan		3,000	19,000
Proceeds from issuance of common stock and common stock warrants	28,661,000	33,820,000	18,000,000
Proceeds from issuance of convertible debt, net			25,907,000
Proceeds from the exercise of warrants	12,298,378	10,166,000
Net cash provided by financing activities	37,311,000	40,152,000	28,229,000
Net increase (decrease) in cash and cash equivalents	10,857,000	10,672,000	(18,266,000)
Cash and cash equivalents
Beginning of year	17,031,000	6,359,000	24,625,000
Ending of year	27,888,000	17,031,000	6,359,000
Supplemental disclosures of cash and non-cash investing and financing transactions
Conversion and exchanges of convertible debt for common stock	10,758,000	2,294,000
Cash paid for interest, net of interest capitalized		4,589,000	4,213,000
Capitalization of interest, from term to 2017 convertible notes			201,000
Non-cash purchase of property, plant and equipment	513,000	890,000	108,000
Accrued offering costs		648,000
Issuance of common stock for services			31,000
Fair value of warrants at issuance and upon exercise, net	$ 6,668,000	$ (7,951,000)	$ 2,400,000