CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($) $ in Thousands	9 Months Ended
	Sep. 25, 2020	Sep. 27, 2019
Cash flows from operating activities:
Net loss	$ (42,736)	$ (11,494)
Adjustments to reconcile net loss to net cash provided by (used in) operating activities:
Amortization of intangibles	3,214	6,242
Depreciation	8,683	8,480
Stock-based compensation	13,737	8,719
Amortization of discount on convertible and other debt	5,451	4,960
Amortization of non-cash warrant	1,307	13,137
Loss on debt extinguishment	834	5,695
Deferred income taxes, net	1,527	75
Foreign currency adjustments	2,537	(1,719)
Provision for excess and obsolete inventories	1,390	704
Provision for doubtful accounts, returns and discounts	1,966	988
Other non-cash adjustments, net	177	1,235
Changes in operating assets and liabilities:
Accounts receivable	5,436	(20,521)
Inventories	(9,301)	(4,170)
Prepaid expenses and other assets	23,685	(5,703)
Accounts payable	(11,047)	(2,839)
Deferred revenue	6,066	8,002
Income taxes payable	(384)	(114)
Accrued and other liabilities	(14,961)	(10,536)
Net cash provided by (used in) operating activities	(2,419)	1,141
Cash flows from investing activities:
Purchases of property and equipment	(26,176)	(4,973)
Net cash used in investing activities	(26,176)	(4,973)
Cash flows from financing activities:
Proceeds from convertible debt	0	115,500
Payments of convertible debt	(25)	(109,603)
Payment of convertible debt issuance costs	(672)	(3,465)
Proceeds from other debts and finance leases	9,398	4,684
Repayment of other debts and finance leases	(6,342)	(6,387)
Proceeds from common stock issued to employees	5,227	5,573
Payment of tax withholding obligations related to net share settlements of restricted stock units	(1,384)	(1,278)
Net cash provided by financing activities	6,202	5,024
Effect of exchange rate changes on cash and cash equivalents	152	(486)
Net increase (decrease) in cash and cash equivalents	(22,241)	706
Cash and cash equivalents at beginning of period	93,058	65,989
Cash and cash equivalents at end of period	70,817	66,695
Supplemental disclosures of cash flow information:
Income tax payments (refunds), net	(426)	980
Interest payments, net	3,216	3,432
Supplemental schedule of non-cash investing and financing activities:
Capital expenditures incurred but not yet paid	3,284	543
Issuance of warrant		$ 16,142
Fair value of Convertible Senior Notes due 2022 used to settle Convertible Senior Notes due 2020	$ 44,357