Condensed Consolidated Statements of Cash Flows (Unaudited) - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016
CASH FLOWS FROM OPERATING ACTIVITIES:
Net loss	$ (47,530)	$ (39,629)
Adjustments to reconcile net loss to net cash used in operating activities:
Depreciation and amortization	1,574	1,325
Stock-based compensation	2,766	2,199
Accretion on asset retirement obligation	29	26
Change in fair value of warrant liabilities	6,739	1,646
Loss on disposal of property and equipment	9	5
Inventory lower of cost or market adjustment	647	928
Amortization of debt discount and interest accrual	2,453	1,806
Changes in operating assets and liabilities:
Accounts receivable	3,158	530
Inventory	(11,143)	(3,370)
Deposits on purchased inventory	(3,593)	(977)
Deferred cost of revenue	(6,481)	(1,438)
Prepaid expenses and other assets	(2,124)	(820)
Accounts payable	2,108	(2,645)
Accrued expenses and other long-term liabilities	2,519	1,106
Customer deposits and deferred revenue	5,175	11,238
Net cash used in operating activities	(43,694)	(28,070)
CASH FLOWS FROM INVESTING ACTIVITIES:
Purchase of property and equipment	(1,117)	(6,672)
Purchase of intangible assets and other assets	0	(12)
Change in restricted cash balance	0	(200)
Net cash used in investing activities	(1,117)	(6,884)
CASH FLOWS FROM FINANCING ACTIVITIES:
Proceeds from common stock private placement, gross	26,100	13,750
Proceeds from draw down of long-term debt, net	0	14,982
Proceeds from the exercise of stock options	247	384
Net cash provided by financing activities	65,026	28,894
NET INCREASE (DECREASE) IN CASH AND CASH EQUIVALENTS	20,215	(6,060)
CASH AND CASH EQUIVALENTS — BEGINNING OF PERIOD	14,198	20,667
CASH AND CASH EQUIVALENTS — END OF PERIOD	34,413	14,607
SUPPLEMENTAL DISCLOSURE OF CASH FLOW INFORMATION:
Cash paid for interest	2,919	2,349
Cash paid for taxes	25	0
SUPPLEMENTAL NON-CASH INVESTING AND FINANCING ACTIVITIES:
Purchase of property and equipment in accounts payable and accrued expenses	277	169
Transfer of property and equipment from inventory	125	117
Offering cost in accounts payable and accrued expenses	0	308
Private Placement
CASH FLOWS FROM FINANCING ACTIVITIES:
Payment of offering costs related to common stock	(300)	(222)
At The Market Offering Program
CASH FLOWS FROM FINANCING ACTIVITIES:
Payment of offering costs related to common stock	(1,147)	0
Proceeds from at-the-market offering of common stock, gross	$ 40,126	$ 0