Condensed Consolidated Statements of Cash Flows (Unaudited) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2016	Mar. 31, 2015
CASH FLOWS FROM OPERATING ACTIVITIES:
Net loss	$ (13,368)	$ (8,455)
Adjustments to reconcile net loss to net cash used in operating activities:
Depreciation and amortization	372	288
Stock-based compensation	556	74
Accretion on asset retirement obligation	9
Change in fair value of convertible preferred stock warrant liability		(66)
Loss on disposal of property and equipment	2
Inventory lower of cost or market adjustment	235
Amortization of debt discount and interest accrual	462	115
Changes in operating assets and liabilities:
Accounts receivable	830	904
Inventory	(4,261)	913
Deposits on purchased inventory	384	(686)
Deferred costs	4,887	(3,619)
Prepaid expenses and other assets	(43)	(508)
Accounts payable	1,957	(2,853)
Accrued expenses and other long-term liabilities	504	(401)
Customer deposits and deferred revenue	(3,016)	4,690
Net cash used in operating activities	(10,490)	(9,604)
CASH FLOWS FROM INVESTING ACTIVITIES:
Purchase of property and equipment	(4,456)	(489)
Net cash used in investing activities	(4,456)	(489)
CASH FLOWS FROM FINANCING ACTIVITIES:
Proceeds from issuance of convertible notes, net		15,729
Payments of long-term debt		(1,328)
Payment of offering costs related to common stock private placement		(272)
Proceeds from the exercise of stock options	8	8
Net cash provided by financing activities	8	14,137
NET INCREASE (DECREASE) IN CASH	(14,938)	4,044
CASH — BEGINNING OF PERIOD	20,667	11,129
CASH — END OF PERIOD	5,729	15,173
SUPPLEMENTAL DISCLOSURE OF CASH FLOW INFORMATION:
Cash paid for interest	621	379
SUPPLEMENTAL NON-CASH INVESTING AND FINANCING ACTIVITIES:
Purchase of fixed assets in accounts payable and accrued expenses	932	28
Transfer of fixed assets from inventory	$ 1,728
Offering cost in accounts payable and accrued expenses		$ 1,216