Condensed Consolidated Statements of Cash Flows (Unaudited) - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016
CASH FLOWS FROM OPERATING ACTIVITIES:
Net loss	$ (36,314)	$ (25,483)
Adjustments to reconcile net loss to net cash used in operating activities:
Depreciation and amortization	1,004	856
Stock-based compensation	1,782	1,245
Accretion on asset retirement obligation	19	17
Change in fair value of warrant liabilities	9,032	0
Loss on disposal of property and equipment	9	2
Inventory lower of cost or market adjustment	0	235
Amortization of debt discount and interest accrual	1,605	1,059
Changes in operating assets and liabilities:
Accounts receivable	2,380	(880)
Inventory	(7,276)	(3,472)
Deposits on purchased inventory	(2,994)	1,059
Deferred cost of revenue	(7,254)	1,237
Prepaid expenses and other assets	(2,096)	(394)
Accounts payable	1,808	1,091
Accrued expenses and other long-term liabilities	976	686
Customer deposits and deferred revenue	13,436	2,172
Net cash used in operating activities	(23,883)	(20,570)
CASH FLOWS FROM INVESTING ACTIVITIES:
Purchase of property and equipment	(776)	(5,748)
Purchase of intangible assets and other assets	0	(12)
Net cash used in investing activities	(776)	(5,760)
CASH FLOWS FROM FINANCING ACTIVITIES:
Proceeds from common stock private placement, gross	26,100	0
Proceeds from draw down of long-term debt, net	0	14,982
Proceeds from the exercise of stock options	193	110
Net cash provided by financing activities	64,388	15,092
NET INCREASE (DECREASE) IN CASH AND CASH EQUIVALENTS	39,729	(11,238)
CASH AND CASH EQUIVALENTS — BEGINNING OF PERIOD	14,198	20,667
CASH AND CASH EQUIVALENTS — END OF PERIOD	53,927	9,429
SUPPLEMENTAL DISCLOSURE OF CASH FLOW INFORMATION:
Cash paid for interest	1,924	1,398
Cash paid for taxes	1	0
SUPPLEMENTAL NON-CASH INVESTING AND FINANCING ACTIVITIES:
Purchase of property and equipment in accounts payable and accrued expenses	248	969
Transfer of property and equipment from inventory	0	117
Offering cost in accounts payable and accrued expenses	6	0
Private Placement [Member]
CASH FLOWS FROM FINANCING ACTIVITIES:
Payment of offering costs related to common stock	(300)	0
At The Market Offering Program [Member]
CASH FLOWS FROM FINANCING ACTIVITIES:
Payment of offering costs related to common stock	(1,129)	0
Proceeds from at-the-market offering of common stock, gross	$ 39,524	$ 0