Condensed Consolidated Statements of Cash Flows (Unaudited) - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017
Operating activities
Net loss	$ (118,930)	$ (67,733)
Adjustments to reconcile net loss to net cash used in operating activities:
Depreciation and amortization	2,511	2,456
Gain on disposal of property and equipment		(32)
Accretion of discounts on marketable securities	(1,146)	(104)
Reversal of deferred rent upon lease amendment		(209)
Stock compensation expense	17,135	10,844
Cost of sales - amortization of intangible assets	8,538
Non-cash interest expense	1,944
Changes in operating assets and liabilities:
Accounts and other receivables	(653)	559
Inventories, net	(12,140)
Prepaid expenses and other current assets	(907)	(1,841)
Other assets	(2,564)	(936)
Accounts payable	2,377	(1,499)
Accrued liabilities and other long term liabilities	6,164	(1,274)
Net cash used in operating activities	(97,671)	(59,769)
Investing activities
Acquisition of technology licenses	(11,000)
Purchases of marketable securities	(187,808)	(192,684)
Proceeds from maturities of marketable securities	212,700	78,298
Purchases of property and equipment, net	(2,838)	(374)
Net cash provided by (used in) investing activities	11,054	(114,760)
Financing activities
Proceeds from long-term debt, net	99,000
Proceeds from issuance of common stock, net		169,187
(Tax withholding) proceeds from exercise of stock options and restricted stock awards, net	(529)	285
Proceeds from Employee Stock Purchase Plan	594	292
Net cash provided by financing activities	99,065	169,764
Effect of exchange rate changes on cash, cash equivalents and restricted cash	(327)	596
Net increase (decrease) in cash, cash equivalents and restricted cash	12,121	(4,169)
Cash, cash equivalents and restricted cash at beginning of period	27,213	24,891
Cash, cash equivalents and restricted cash at end of period	39,334	20,722
Supplemental disclosure of cash flow information
Cash paid during the period for interest	4,643
Release of accrual for litigation settlement and insurance recovery (Note 6)		4,050
Non-cash investing and financing activities:
Disposal of fully depreciated property and equipment	199
Non-cash acquisition of technology license	$ 12,773
Common stock issuance costs - cash not paid as of period end		$ 110