Unaudited Condensed Consolidated Statements of Cash Flows - USD ($) $ in Thousands	9 Months Ended
	Sep. 27, 2020	Sep. 29, 2019
Cash flows from operating activities:
Net income	$ 27,345	$ 26,211
Adjustments to reconcile net income to net cash provided by (used in) operating activities:
Depreciation and amortization	14,243	14,577
Stock-based compensation	22,726	20,183
Impairment of long-term investments	5,372	0
Deferred income taxes	1,574	503
Provision for excess and obsolete inventory	6,353	2,921
Other	278	253
Changes in assets and liabilities:
Accounts receivable	(62,837)	55,597
Inventories	84,834	(34,634)
Prepaid expenses and other assets	3,975	2,960
Accounts payable	6,862	(54,574)
Accrued employee compensation	10,924	(13,562)
Other accrued liabilities	5,668	(45,240)
Deferred revenue	5,302	(4,152)
Income taxes payable	2,443	(7,087)
Net cash provided by (used in) operating activities	135,062	(36,044)
Cash flows from investing activities:
Purchases of short-term investments	(288)	(282)
Proceeds from maturities of short-term investments	286	70,786
Purchases of property and equipment	(6,112)	(11,797)
Purchases of long-term investments	(6,300)	(5,484)
Net cash provided by (used in) investing activities	(12,414)	53,223
Cash flows from financing activities:
Repurchases of common stock	(22,508)	(52,365)
Restricted stock unit withholdings	(4,750)	(6,058)
Proceeds from exercise of stock options	11,016	4,582
Proceeds from issuance of common stock under employee stock purchase plan	3,878	3,617
Net cash used in financing activities	(12,364)	(50,224)
Net increase (decrease) in cash and cash equivalents	110,284	(33,045)
Cash and cash equivalents, at beginning of period	190,208	201,047
Cash and cash equivalents, at end of period	300,492	168,002
Non-cash investing and financing activities:
Change in accounts payable and other accrued liabilities relating to property and equipment additions	$ (1,046)	$ 3,174