Consolidated Statements of Cash Flows - USD ($) shares in Thousands, $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Operating activities
Net loss	$ (124,827)	$ (128,154)	$ (137,628)
Adjustments to reconcile net loss to net cash used in operating activities:
Depreciation and amortization	7,730	7,501	7,143
Non-cash lease expense	7,748
Impairment of assets	1,671	1,544	576
Stock-based compensation	28,624	14,198	11,402
Inventory excess adjustments	321	265	502
Provision for doubtful accounts	1,141	(41)	143
Premium amortization and discount accretion on investment securities	945	238	857
(Gain) loss realized on investment securities	(16)	43	64
(Gain) loss on sales of property and equipment		(12)	12
Loss (gain) from changes in fair value of warrants		4,118	(1,148)
Interest accrued for borrowings and claims related settlement		2,172	488
Amortization of debt discount	457	391	154
Other non-cash (benefits)	(51)
Gain on disposal of business	(14,388)
Changes in operating assets and liabilities
Accounts receivable	2,418	(18,093)	6,315
Inventory	917	(4,900)	(3,086)
Prepaid expenses and other current assets	(13,956)	2,643	(1,515)
Other assets	(9,099)	335	600
Accounts payable	(6,262)	3,781	217
Accrued compensation	3,419	3,069	(1,467)
Other accrued liabilities	8,606	(1,820)	14,919
Deferred revenue	40,848	42,769	846
Deferred rent, net of current portion		(628)	1,452
Other long-term liabilities	310		1,329
Net cash used in operating activities	(63,444)	(70,581)	(97,825)
Investing activities
Purchases of investments	(446,626)	(170,268)	(272,819)
Proceeds from sale of investments	1,666	37,387	65,270
Proceeds from maturity of investments	173,900	131,600	231,200
Net proceeds from disposal of business	9,675
Purchases of property and equipment, net	(4,968)	(3,880)	(9,867)
Net cash (used in) provided by investing activities	(266,353)	(5,161)	13,784
Financing activities
Proceeds from exercise of stock options	13,041	13,331	2,315
Proceeds from issuance of common stock under employee stock purchase plan	4,323	3,617	3,344
Proceeds from equity offering, net of issuance costs	323,410	96,777
Borrowings under long-term debt facility			75,000
Payment for debt issuance costs on long-term debt facility			287
Net cash provided by financing activities	340,774	113,725	80,372
Net increase (decrease) increase in cash, cash equivalents and restricted cash	10,977	37,983	(3,669)
Cash, cash equivalents and restricted cash, beginning of period	51,004	13,021	16,690
Cash, cash equivalents and restricted cash, end of period	61,981	51,004	13,021
Supplemental disclosure of cash flow information:
Cash paid for income taxes	2,154	332	177
Cash paid for interest	12,455	7,914	3,568
Non-cash investing and financing activities:
Purchases of property and equipment in accounts payable and accruals	$ 3,706	$ 268	$ 447
Issuance of common stock for exercise of warrants		6,762
Issuance of common stock for lender's commitment to debt financing			2,448