Condensed Consolidated Statements of Cash Flows (Unaudited) - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2016	Sep. 30, 2015
CASH FLOWS FROM OPERATING ACTIVITIES:
Net loss	$ (39,629)	$ (30,889)
Adjustments to reconcile net loss to net cash used in operating activities:
Depreciation and amortization	1,325	913
Stock-based compensation	2,199	531
Accretion on asset retirement obligation	26
Change in fair value of warrant liability	1,646	(45)
Loss on disposal of property and equipment	5
Inventory lower of cost or market adjustment	928	995
Write-off of deferred offering cost		2,920
Amortization of debt discount and interest accrual	1,806	573
Changes in operating assets and liabilities:
Accounts receivable	530	903
Inventory	(3,370)	(2,406)
Deposits on purchased inventory	(977)	(2,223)
Deferred cost of revenue	(1,438)	409
Prepaid expenses and other assets	(820)	(664)
Accounts payable	(2,645)	(6,048)
Notes payable		(240)
Accrued expenses and other long-term liabilities	1,106	392
Customer deposits and deferred revenue	11,238	3,574
Net cash used in operating activities	(28,070)	(31,305)
CASH FLOWS FROM INVESTING ACTIVITIES:
Purchase of property and equipment	(6,672)	(2,906)
Purchase of intangibles and other assets	(12)
Change in restricted cash balance	(200)	500
Net cash used in investing activities	(6,884)	(2,406)
CASH FLOWS FROM FINANCING ACTIVITIES:
Proceeds from issuance of convertible preferred stock, net of issuance cost		15,729
Proceeds from draw down of long-term debt, net of debt discount	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	384	19
Net cash provided by financing activities	28,894	54,646
NET INCREASE (DECREASE) IN CASH AND CASH EQUIVALENTS	(6,060)	20,935
CASH AND CASH EQUIVALENTS — BEGINNING OF PERIOD	20,667	11,129
CASH AND CASH EQUIVALENTS — END OF PERIOD	14,607	32,064
SUPPLEMENTAL DISCLOSURE OF CASH FLOW INFORMATION:
Cash paid for interest	2,349	1,711
SUPPLEMENTAL NON-CASH INVESTING AND FINANCING ACTIVITIES:
Purchase of property and equipment in accounts payable and accrued expenses	169	309
Transfer of property and equipment from inventory	117
Offering cost in accounts payable and accrued expenses	308	605
Fair value of common stock warrants issued to placement agents for service in 2015 private placement		316
Conversion of convertible preferred stock to common stock in connection with the Merger		160,839
Conversion of convertible preferred stock warrants into common stock warrants		93
2016 Private Placement
CASH FLOWS FROM FINANCING ACTIVITIES:
Proceeds from private placement, gross	13,750
Payment of offering costs related to private placement	$ (222)
2015 Private Placement
CASH FLOWS FROM FINANCING ACTIVITIES:
Proceeds from private placement, gross		29,447
Payment of offering costs related to private placement		$ (2,302)