Consolidated Statements of Cash Flows (Unaudited) - USD ($) $ in Thousands	9 Months Ended
	Sep. 26, 2020	Sep. 28, 2019
Cash flows from operating activities:
Net income	$ 31,403	$ 29,506
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization	19,263	24,682
Stock-based compensation expense	30,228	13,335
Reduction in the carrying amount of right-of-use assets	4,464	4,372
Amortization of debt issuance costs and discount	300	1,539
Impairment of operating lease right-of-use asset (recorded in Restructuring charges)	0	977
Loss on refinancing of long-term debt	0	2,235
Other non-cash adjustments	(101)	(63)
Changes in assets and liabilities:
Accounts receivable, net	(8,072)	13,457
Inventories	(4,508)	7,424
Prepaid expenses and other assets	(3,516)	(8,741)
Accounts payable and accrued expenses	1,861	(196)
Accrued payroll obligations	1,744	2,063
Operating lease liabilities, current and long-term portions	(4,331)	(5,571)
Income taxes payable	223	(202)
Net cash provided by operating activities	68,958	84,817
Cash flows from investing activities:
Capital expenditures	(9,781)	(11,729)
Cash paid for software licenses	(6,850)	(5,745)
Proceeds from sales of and maturities of short-term marketable securities	0	9,655
Net cash used in investing activities	(16,631)	(7,819)
Cash flows from financing activities:
Restricted stock unit tax withholdings	(19,934)	(7,813)
Proceeds from issuance of common stock	7,145	16,178
Proceeds from issuance of long-term debt	50,000	206,500
Original issue discount and debt issuance costs	0	(2,086)
Repayment of debt	(26,250)	(311,408)
Net cash provided by (used in) financing activities	10,961	(98,629)
Effect of exchange rate change on cash	899	(7)
Net increase in cash and cash equivalents	64,187	(21,638)
Beginning cash and cash equivalents	118,081	119,051
Ending cash and cash equivalents	182,268	97,413
Interest paid	2,849	9,932
Operating lease payments	5,786	6,540
Income taxes paid, net of refunds	2,317	1,922
Accrued purchases of plant and equipment	549	1,841
Operating lease right-of-use assets obtained in exchange for lease obligations	$ 2,274	$ 404