Condensed Consolidated Statements of Cash Flows (Unaudited) - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2016	Jun. 30, 2015
CASH FLOWS FROM OPERATING ACTIVITIES:
Net loss	$ (25,483)	$ (20,629)
Adjustments to reconcile net loss to net cash used in operating activities:
Depreciation and amortization	856	591
Stock-based compensation	1,245	148
Accretion on asset retirement obligation	17
Change in fair value of convertible preferred stock warrant liability		(51)
Loss on disposal of property and equipment	2
Inventory lower of cost or market adjustment	235	308
Write-off of deferred offering cost		2,920
Amortization of debt discount and interest accrual	1,059	123
Changes in operating assets and liabilities:
Accounts receivable	(880)	904
Inventory	(3,472)	(358)
Deposits on purchased inventory	1,059	(1,427)
Deferred cost of revenue	1,237	(3,828)
Prepaid expenses and other assets	(394)	(386)
Accounts payable	1,091	(3,008)
Accrued expenses and other long-term liabilities	686	(102)
Customer deposits and deferred revenue	2,172	4,509
Net cash used in operating activities	(20,570)	(20,286)
CASH FLOWS FROM INVESTING ACTIVITIES:
Purchase of property and equipment	(5,748)	(1,137)
Purchase of intangibles and other assets	(12)
Change in restricted cash balance		500
Net cash used in investing activities	(5,760)	(637)
CASH FLOWS FROM FINANCING ACTIVITIES:
Proceeds from issuance of convertible notes, net		15,729
Proceeds from draw down of long-term debt, net	14,982	27,381
Payments of long-term debt		(15,000)
Payment of offering costs related to initial public offering		(628)
Proceeds from the exercise of stock options	110	10
Net cash provided by financing activities	15,092	27,492
NET INCREASE (DECREASE) IN CASH AND CASH EQUIVALENTS	(11,238)	6,569
CASH AND CASH EQUIVALENTS — BEGINNING OF PERIOD	20,667	11,129
CASH AND CASH EQUIVALENTS — END OF PERIOD	9,429	17,698
SUPPLEMENTAL DISCLOSURE OF CASH FLOW INFORMATION:
Cash paid for interest	1,398	963
SUPPLEMENTAL NON-CASH INVESTING AND FINANCING ACTIVITIES:
Purchase of property and equipment in accounts payable and accrued expenses	969
Transfer of property and equipment from inventory	$ 117
Deferred offering cost in accounts payable and accrued expenses		$ 532