CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS (Unaudited) - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017
Operating activities:
Net loss	$ (13,379)	$ (17,573)
Adjustments to reconcile net loss to net cash used for operating activities:
Depreciation and amortization expense	1,133	1,186
Stock compensation expense	5,739	2,053
Change in fair value of warrants	2,524	512
Inventory provision	303	232
Loss on sale of fixed assets	23	0
Foreign currency translation loss	49	20
Change in operating assets and liabilities:
Inventory	(148)	(793)
Deferred rent	(132)	91
Accounts receivable	2,742	1,663
Prepaid and other current assets	(758)	(202)
Accounts payable	(1,212)	(1,068)
Accrued expenses	19	(9)
Other assets and liabilities, net	74	(129)
Net cash used for operating activities	(3,023)	(14,017)
Investing activities:
Purchases of short term investments	(44,480)	0
Expenditures for property, plant and equipment	(2,101)	(792)
Net cash used in investing activities	(46,581)	(792)
Financing activities:
Net proceeds from equity offering	70,028	0
Net proceeds from common stock issuance due to stock option exercises	3,310	7,549
Proceeds from exercise of warrants	2,716	0
Other	(23)	(252)
Net cash provided by financing activities	76,031	7,297
Net increase (decrease) in cash and cash equivalents	26,427	(7,512)
Cash and cash equivalents at beginning of period	26,862	22,978
Cash and cash equivalents at end of period	$ 53,289	$ 15,466