Condensed Consolidated Statements of Cash Flows - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2016	Jun. 30, 2015
Cash flows from operating activities
Net loss	$ (16,059)	$ (22,899)
Adjustments to reconcile net loss to net cash used in operating activities:
Depreciation and amortization	1,150	1,707
Loss (gain) on disposal of equipment	58	(35)
Share-based compensation	1,327	2,185
Non-cash interest expense	657	265
Net changes in operating assets and liabilities:
Accounts receivable	(2,196)	(1,164)
Inventories	1,068	2,037
Prepaid Expenses and other assets	403	130
Deferred cost of product revenues	(430)	200
Accounts payable	196	(2,263)
Accrued and other liabilities	(1,419)	223
Accrued interest due to related parties	425
Deferred revenue	1,449	(375)
Deferred revenue from related parties	(168)	(382)
Customer refund liabilities		(25)
Net cash used in operating activities	(13,539)	(20,396)
Cash flows from investing activities
Purchases of property, plant and equipment	(93)	(1,398)
Proceeds from the sale of equipment		7
Net cash used in investing activities	(93)	(1,391)
Cash flows from financing activities
Repayment of debt	(129)	(192)
Repayment of capital leases	(346)	(1,149)
Change in restricted cash	15,412
Exercise of stock options	16
Net cash provided by (used) in financing activities	14,953	(1,341)
Net increase (decrease) in cash and cash equivalents	1,321	(23,128)
Cash and cash equivalents, beginning of period	19,838	35,324
Cash and cash equivalents, end of period	21,159	12,196
Supplemental disclosure of cash flow information
Cash paid for interest, net of capitalized interest of $0 and $4 for the six months ended June 30, 2016 and 2015, respectively	2,595	1,069
Supplemental disclosure of non-cash investing and financing activities
Property, plant and equipment included in accounts payable and accrued liabilities	24	12
Equipment acquired under capital leases	$ 1,586	$ 787