Consolidated Statements of Cash Flows - USD ($) $ in Thousands	3 Months Ended
	Apr. 03, 2022	Apr. 04, 2021
Cash flows from operating activities:
Net income	$ 67,333	$ 69,848
Adjustments to reconcile net income to net cash provided by operating activities:
Stock-based compensation expense	15,056	12,009
Depreciation of property, plant, and equipment	4,117	4,259
Loss (gain) on disposal of property, plant, and equipment	0	3
Amortization of intangible assets	840	927
Excess and obsolete inventory charges	379	705
Amortization of discounts or premiums on investments	1,402	586
Realized loss (gain) on sale of investments	36	0
Change in deferred income taxes	(3,891)	1,250
Accounts receivable	(24,700)	(3,495)
Unbilled revenue	2,144	3,958
Inventories	(23,900)	(1,323)
Prepaid expenses and other current assets	4,212	(10,882)
Accounts payable	708	4,760
Accrued expenses	(28,718)	(15,973)
Accrued income taxes	16,745	1,651
Deferred revenue and customer deposits	18,712	30,641
Other	(958)	(285)
Net cash provided by operating activities	49,517	98,639
Cash flows from investing activities:
Purchases of investments	(39,155)	(298,911)
Maturities and sales of investments	112,976	160,552
Purchases of property, plant, and equipment	(4,585)	(2,436)
Net cash provided by (used in) investing activities	69,236	(140,795)
Cash flows from financing activities:
Net proceeds from issuance of common stock under stock plans	3,594	34,744
Repurchase of common stock	(130,405)	(6,479)
Payment of dividends	(11,303)	(10,595)
Net cash provided by (used in) financing activities	(138,114)	17,670
Effect of foreign exchange rate changes on cash and cash equivalents	(1,031)	(1,899)
Net change in cash and cash equivalents	(20,392)	(26,385)
Cash and cash equivalents at beginning of period	186,161	269,073
Cash and cash equivalents at end of period	$ 165,769	$ 242,688