Condensed Consolidated Statements of Cash Flows - USD ($) $ in Thousands	3 Months Ended	9 Months Ended
	Sep. 30, 2019	Sep. 30, 2020
Operating activities
Net loss	$ (89,644)	$ (153,331)
Adjustments to reconcile net loss to net cash used in operating activities:
Depreciation and amortization	5,921	6,215
Premium amortization and discount accretion on investment securities	400	3,333
Stock-based compensation	20,102	34,406
Non-cash lease expense	5,807	5,819
Amortization of debt discount and issuance cost	336	149
Inventory reserve adjustments	719	(180)
Impairment of assets	1,310
Impairment of right-of-use assets	361
Provision for doubtful accounts	497
Other non-cash benefits	(22)	(135)
Gain on disposal of business	(14,388)
Provision for credit losses		1,445
Loss on Debt Extinguishment		5,848
Accretion of Convertible Note		4,514
Changes in operating assets and liabilities
Accounts receivable	(2,491)	(17,940)
Inventory	400	(7,803)
Prepaid expenses and other current assets	(9,321)	(7,288)
Other assets	(9,299)	97
Accounts payable	(5,194)	(1,613)
Accrued compensation	1,569	6,362
Other accrued liabilities	1,683	16,362
Deferred revenue	42,864	(5,470)
Net cash used in operating activities	(48,390)	(109,210)
Investing activities
Purchases of investments	(197,009)	(479,037)
Proceeds from sale of investments		11,500
Proceeds from maturity of investments	118,780	247,315
Net proceeds from disposal of business	9,675
Purchases of property and equipment, net	(2,554)	(12,073)
Net cash provided by investing activities	(71,108)	(232,295)
Financing activities
Proceeds from exercise of stock options	10,416	15,782
Proceeds from issuance of common stock under employee stock purchase plan	2,147	3,062
Proceeds from Convertible Note, net of issuance costs		278,316
Loan payment		(78,757)
Proceeds from public offering, net of issuance costs	107,595	270,650
Net cash provided by financing activities	120,158	489,053
Net increase in cash, cash equivalents and restricted cash	660	147,548
Cash, cash equivalents and restricted cash, beginning of period		61,981
Cash, cash equivalents and restricted cash, end of period	51,664	209,529
Supplemental disclosure of cash flow information:
Cash paid for interest	9,894	3,137
Supplemental non-cash investing and financing activities:
Obtaining right-of-use assets in exchange for lease liabilities	28,191
Purchases of property and equipment in accounts payable and accruals	$ 56	$ 2,814