Consolidated Statements of Cash Flows - USD ($)	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Operating Activities
Net loss	$ (27,976,000)	$ (24,630,000)	$ (37,228,000)
Adjustments to reconcile net loss to net cash used in operating activities:
Loss/(Gain) from the change in fair value of derivative warrant liability	2,976,000	(5,101,000)	(1,783,000)
(Gain) from the change in fair value of the embedded derivative to the 2020 Notes	(2,637,000)	(1,751,000)
Loss from the change in fair value of 2017 Notes		339,000	4,204,000
Loss on exchange or conversion of debt	2,202,000	4,933,000	763,000
Loss on extinguishment of warrant liability			918,000
Loss on issuance of equity			1,519,000
Stock-based compensation	571,000	421,000	886,000
Depreciation and amortization	6,520,000	6,641,000	6,747,000
Non-cash interest expense	1,706,000	962,000	3,977,000
Other non-cash expenses	6,000		(1,000)
Changes in operating assets and liabilities:
Accounts receivable	528,000	68,000	269,000
Inventories	1,196,000	(904,000)	29,000
Prepaid expenses and other current assets	(630,000)	137,000	(119,000)
Accounts payable, accrued expenses, and long-term liabilities	(313,000)	(1,742,000)	(697,000)
Net cash used in operating activities	(15,851,000)	(20,627,000)	(20,516,000)
Investing Activities
Acquisitions of property, plant and equipment	(2,233,000)	(1,906,000)	(5,938,000)
Proceeds from sales tax refund for property, plant and equipment
Net cash used in investing activities	(2,233,000)	(1,906,000)	(5,938,000)
Financing Activities
Payments on secured debt		(9,791,000)	(504,000)
Debt and equity offering costs	(392,000)	(1,095,000)	(3,144,000)
Proceeds from issuance of common stock and common stock warrants	39,394,000	11,044,000	28,661,000
Proceeds from the exercise of warrants	1,263,766	3,429,000	12,298,000
Net cash provided by financing activities	40,265,000	3,587,000	37,311,000
Net increase (decrease) in cash and cash equivalents	22,181,000	(18,946,000)	10,857,000
Beginning of year	11,553,000	30,499,000	19,642,000
Ending of year	33,734,000	11,553,000	30,499,000
Conversion and exchanges of convertible debt for common stock	3,701,000	8,652,000	10,758,000
Cash paid for interest	1,945,000	2,554,000	3,694,000
Non-cash purchase of property, plant and equipment	919,000	27,000	513,000
Discount due to exchange of 2017 Notes for 2020 Notes		3,009,000
Fair value of 2020 Notes embedded derivative upon exchange	2,193,000	6,975,000
Fair value of warrants at issuance and upon exercise, net	$ 4,905,000	$ (4,353,000)	$ 6,668,000