CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019
Operating Activities
Net loss	$ (93,952)	$ (7,651)
Adjustments to reconcile net loss to net cash (used in) provided by operating activities:
Depreciation and amortization	14,644	1,728
Amortization of lease right-of-use assets	2,577	1,396
Amortization of debt discount and issuance costs	557
Deferred income tax benefit	(8,254)
Loss on disposal of fixed assets	15	7
Stock-based compensation	28,073	15,376
Change in fair value of cash settled stock options	(3,172)
Unrealized foreign currency losses		(204)
Amortization of discount on short-term investments	33	(221)
Other liabilities	2,324	2,090
Changes in operating assets and liabilities:
Accounts receivable, net	11,556	(3,353)
Inventory, net	21,396	(752)
Prepaid expenses and other current assets	(1,606)	462
Accounts payable and accrued liabilities	1,998	(2,011)
Other assets	(211)	(57)
Net cash (used in) provided by operating activities	(24,022)	6,810
Investing activities
Purchases of short-term investments	(60,883)	(39,896)
Proceeds from sales and maturities of short-term investments	45,011	41,069
Purchases of property and equipment	(3,509)	(2,523)
Investment in company-owned life insurance	(658)	(962)
Net cash used in investing activities	(20,039)	(2,312)
Financing activities
Proceeds from convertible senior notes	287,500
Payment of convertible senior notes transaction costs	(9,614)
Purchase of capped calls related to issuance of convertible senior notes	(35,679)
Proceeds from exercise of stock options	6,590	9,171
Proceeds from share purchases under Employee Stock Purchase Plan	1,278	902
Payment of employee taxes related to vested restricted stock units	(2,013)	(4,348)
Net cash provided by financing activities	248,062	5,725
Effect of exchange rate changes on cash and cash equivalents	543	21
Net increase in cash, cash equivalents and restricted cash	204,544	10,244
Cash, cash equivalents and restricted cash at beginning of period	71,756	38,596
Cash, cash equivalents and restricted cash at end of period	276,300	48,840
Supplemental disclosures of cash flow information
Taxes paid	$ 294	$ 91