Statements of Cash Flows - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Cash flows from operating activities:
Net loss	$ (40,166)	$ (41,230)	$ (5,811)
Adjustments to reconcile net loss to net cash used in operating activities:
Goodwill impairment		14,278
Depreciation and amortization	1,177	318	275
Provision for doubtful accounts	437	233	39
Provision for warranties	71	385	447
Provision for inventory	1,384	469
Change in fair value of warrants	39	(360)	220
Change in fair value of contingent consideration	37
Non-cash interest expense	3	1,386	490
Stock-based compensation expense	3,236	2,382	594
Loss on disposal of property and equipment	124
Deferred income taxes	61
Changes in assets and liabilities:
Accounts receivable	927	715	875
Prepaid expenses, other current assets and other assets	(529)	147	(864)
Inventories	2,390	(898)	1,359
Insurance recovery receivable	(9,375)
Accounts payable	(564)	1,546	(2,266)
Accrued and other liabilities	(1,422)	1,571	1,385
Legal settlement payable	10,900
Customer deposits	(3,160)	874	3,707
Net cash (used in) provided by operating activities	(34,430)	(18,184)	450
Cash flows from investing activities:
Purchase of property and equipment	(1,126)	(1,128)	(439)
Business acquisition	(11,709)
Net cash used in investing activities	(12,835)	(1,128)	(439)
Cash flows from financing activities:
Proceeds from exercise of stock options	923	119	38
Proceeds from issuance of common stock, net of underwriters discount		62,040	80,213
Proceeds from issuance of common stock under ESPP	753	564
Deferred equity issuance costs, IPO		(71)	(3,107)
Deferred equity issuance costs, follow-on offering		(643)
Proceeds from issuance of long-term debt			10,000
Repayment of long-term debt		(26,625)
Deferred financing costs			(148)
Net cash provided by financing activities	1,676	35,384	86,996
Net (decrease) increase in cash and cash equivalents	(45,589)	16,072	87,007
Cash and cash equivalents at:
Beginning of period	112,801	96,729	9,722
End of period	67,212	112,801	96,729
Supplemental disclosure of cash flow information:
Interest paid	96	1,884	1,577
Supplemental disclosure of non-cash investing and financing activities:
Accrued equity issuance costs			71
Property and equipment in accounts payable	939	$ 22	$ 44
Acquisition of business, deferred and contingent consideration obligations at fair value	$ 1,600