Condensed Statements of Cash Flows - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2016	Mar. 31, 2015
Cash flows from operating activities:
Net loss	$ (11,937)	$ (3,384)
Adjustments to reconcile net loss to net cash used in operating activities:
Depreciation and amortization	144	83
Provision for doubtful accounts	300	20
Provision for warranties	15	143
Provision for inventory	263	21
Change in fair value of warrants	15	82
Non-cash interest expense	1	143
Stock-based compensation expense	739	543
Loss on disposal of property and equipment	122
Changes in assets and liabilities:
Accounts receivable	1,236	(469)
Prepaid expenses, other current assets and other assets	(399)	(126)
Inventories	279	585
Accounts payable	(622)	(913)
Accrued and other liabilities	(1,236)	(382)
Customer deposits	(1,317)	681
Net cash used in operating activities	(12,397)	(2,973)
Cash flows from investing activities:
Purchase of property and equipment	(606)	(137)
Business acquisition	(6,759)
Net cash used in investing activities	(7,365)	(137)
Cash flows from financing activities:
Proceeds from exercise of stock options	24	38
Proceeds from issuance of common stock under ESPP	430
Deferred equity issuance costs, IPO		(71)
Net cash provided by (used in) financing activities	454	(33)
Net decrease in cash and cash equivalents	(19,308)	(3,143)
Cash and cash equivalents at:
Beginning of period	112,801	96,729
End of period	93,493	93,586
Supplemental disclosure of cash flow information:
Interest paid		525
Supplemental disclosure of non-cash investing and financing activities:
Property and equipment in accounts payable		$ 161
Acquisition of business, deferred and contingent consideration obligations at fair value	$ 550