CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($) $ in Thousands	3 Months Ended
	Dec. 31, 2023	Dec. 31, 2022
Cash flows from operating activities:
Net income	$ 121,065	$ 97,643
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization	2,824	4,280
Share-based compensation	31,574	29,702
Deferred income taxes	(4,435)	(8,507)
Net (gain) loss on marketable securities	(2,884)	348
Non-cash operating lease costs	3,500	3,779
Provision for doubtful accounts	419	369
Gain (Loss) on Disposition of Assets	0	1,941
Net loss on sales and abandonment of property and equipment	400	16
Changes in operating assets and liabilities:
Accounts receivable	27,399	8,704
Prepaid expenses and other assets	(13,457)	(5,823)
Accounts payable	(642)	168
Accrued compensation and employee benefits	(35,141)	(37,883)
Other liabilities	(16,490)	(7,955)
Deferred revenue	7,988	9,540
Net cash provided by operating activities	122,120	92,440
Cash flows from investing activities:
Purchases of property and equipment	(1,361)	(850)
Proceeds from sales of marketable securities	13,167	2,393
Purchases of marketable securities	(14,224)	(4,558)
Cash transferred, net of proceeds, from product line asset sale	0	(7,575)
Net cash used in investing activities	(2,418)	(10,590)
Cash flows from financing activities:
Proceeds from revolving line of credit and term loan	170,000	169,000
Payments on revolving line of credit and term loan	(70,750)	(102,750)
Proceeds from issuance of treasury stock under employee stock plans	4,499	1,995
Taxes paid related to net share settlement of equity awards	(131,911)	(72,865)
Repurchases of common stock	(71,704)	(75,004)
Net cash used in financing activities	(99,866)	(79,624)
Effect of exchange rate changes on cash	3,807	4,428
Increase in cash and cash equivalents	23,643	6,654
Cash and cash equivalents, beginning of period	136,778	133,202
Cash and cash equivalents, end of period	160,421	139,856
Supplemental disclosures of cash flow information:
Cash paid for income taxes, net of refunds of $10 and $8 during the quarters ended December 31, 2023 and 2022, respectively	4,926	13,412
Cash paid for interest	38,236	37,730
Supplemental disclosures of non-cash investing activities:
Purchase of property and equipment included in accounts payable	$ 178	$ 37