CONDENSED CONSOLIDATED STATEMENT OF CASH FLOWS - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Cash flows from operating activities:
Net loss	$ (20,812)	$ (14,200)
Adjustments to reconcile net loss to net cash used in operating activities:
Depreciation	539	505
Amortization of intangible assets	5	3
Amortization of investment discount	19	121
Equity-based compensation	5,602	3,215
Non-cash interest expense	158	0
Loss on disposal of property and equipment	11	0
(Increase) decrease in assets:
Accounts receivable	881	(522)
Inventory	(1,917)	(4,155)
Prepaid expense and other	(653)	(457)
Other current assets	(336)	(280)
Increase (decrease) in liabilities:
Accounts payable	701	276
Accrued liabilities	733	(4)
Deferred revenue and income	(1,003)	29
Deferred compensation	4	0
Net cash used in operating activities	(16,068)	(15,469)
Cash flows from investing activities:
Purchases of equipment	(1,294)	(229)
Purchases of available-for-sale securities	(9,356)	(4,562)
Sales of available-for-sale securities	3,000	0
Maturity of available-for-sale securities	20,125	8,845
Net cash provided in investing activities	12,475	4,054
Cash flows from financing activities:
Issuance of common stock net of issuance costs	134	189
Exercise of options and warrants	1,112	1,844
Proceeds from issuance of convertible note	150,000	0
Prepayment of forward stock repurchase transaction	(45,069)	0
Payment of debt issuance costs	(4,330)	0
Net cash provided by financing activities	101,847	2,033
Effect of exchange rate on cash:	80	55
Increase (decrease) in cash and cash equivalents	98,334	(9,327)
Cash and cash equivalents, beginning of period	28,513	19,244
Cash and cash equivalents, end of period	$ 126,847	$ 9,917