CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($) $ in Thousands		9 Months Ended
		Sep. 26, 2020	Sep. 28, 2019
Cash Flows from Operating Activities:
Net loss		$ (196,799)	$ (320,024)
Adjustments to reconcile net loss to net cash used in operating activities:
Depreciation and amortization		74,263	91,181
Non-cash restructuring charges and related costs		2,893	17,194
Amortization of debt discount and issuance costs		20,475	14,107
Operating lease expense		14,123	25,922
Stock-based compensation expense		36,542	31,565
Other, net		3,891	579
Changes in assets and liabilities:
Accounts receivable		55,252	27,521
Inventory		63,201	(23,339)
Prepaid expenses and other assets		(25,479)	(53,470)
Accounts payable		(117,824)	16,487
Accrued liabilities and other expenses		(73,509)	23,190
Deferred revenue		(21,545)	(8,073)
Net cash used in operating activities		(164,516)	(157,160)
Cash Flows from Investing Activities:
Proceeds from sale of non-marketable equity investments		0	1,009
Proceeds from maturities of investments		0	26,584
Acquisition of business, net of cash acquired		0	(10,000)
Proceeds from sale of assets		0	778
Purchase of property and equipment, net		(27,148)	(28,331)
Net cash used in investing activities		(27,148)	(9,960)
Cash Flows from Financing Activities:
Proceeds from issuance of common stock from at-the-market equity offering, net of issuance costs of $954		31,022	0
Proceeds from issuance of 2027 Notes		194,500	0
Proceeds from revolving line of credit		55,000	37,334
Repayment of revolving line of credit		(8,000)	0
Repayment of third party manufacturing funding		(5,346)	0
Payment of debt issuance cost		(2,437)	(124)
Repayment of mortgage payable		(233)	(197)
Principal payments on financing lease obligations		(1,050)	0
Proceeds from issuance of common stock		15,352	12,053
Minimum tax withholding paid on behalf of employees for net share settlement		(1,959)	(393)
Net cash provided by financing activities		276,849	48,673
Effect of exchange rate changes on cash and restricted cash		(2,198)	(3,260)
Net change in cash, cash equivalents and restricted cash		82,987	(121,707)
Cash, cash equivalents and restricted cash at beginning of period		132,797	242,337
Cash, cash equivalents and restricted cash at end of period	[1]	215,784	120,630
Supplemental disclosures of cash flow information:
Cash paid (refund) for income taxes, net		(4,962)	15,924
Cash paid for interest		14,415	13,369
Supplemental schedule of non-cash investing and financing activities:
Unpaid debt issuance cost		31	1,931
Third-party manufacturer funding for transfer expenses incurred		0	6,541
Transfer of inventory to fixed assets		453	2,440
Restricted Cash and Cash Equivalents [Abstract]
Total cash, cash equivalents and restricted cash	[1]	215,784	$ 120,630
Stock issuance costs		$ 954

[1] Reconciliation of cash, cash equivalents and restricted cash to the condensed consolidated balance sheets: September 26,
2020September 28,
2019 (In thousands)Cash and cash equivalents$196,546 $94,804 Short-term restricted cash4,503 — Long-term restricted cash14,735 25,826 Total cash, cash equivalents and restricted cash$215,784 $120,630