Restatement - Statements of Cash Flows (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Mar. 31, 2022	Mar. 31, 2021	Mar. 31, 2022	Mar. 31, 2021
Operating activities:
Net income	$ 1,013	$ 1,019	$ 4,137	$ 3,186
Adjustments to reconcile net income to net cash provided by operating activities:
Stock-based compensation expense			6,429	5,715
Amortization of intangible assets	2,400	1,700	4,525	3,352
Depreciation and amortization			555	774
Amortization of investment premiums & other			1,109	315
Accretion and amortization on debt securities			3,453	1,147
Net changes in estimated fair value of acquisition-related contingent consideration			(780)	0
Deferred taxes			(523)	(464)
Changes in assets and liabilities:
Accounts receivable			(6,171)	1,444
Contract assets			345	2,177
Other assets			498	(1,474)
Accounts payable			3,769	(1,047)
Accrued payroll and related taxes			(4,693)	(1,305)
Deferred revenue			(3,126)	2,379
Other liabilities			159	(138)
Net cash provided by operating activities			9,686	16,061
Investing activities:
Purchases of investments			(47,818)	(147,524)
Sales and maturities of investments			173,316	23,441
Acquisitions, net of cash acquired			(126,607)	0
Purchases of property and equipment			(634)	(660)
Net cash used in investing activities			(1,743)	(124,743)
Financing activities:
Proceeds from the issuance of equity plan common stock			1,128	2,751
Repurchases and retirements of common stock			(14,828)	0
Principal payments on other borrowings			(36)	(39)
Net cash provided by (used in) financing activities			(13,736)	142,635
Foreign currency effect on cash and cash equivalents			(535)	(4)
Net increase (decrease) in cash and cash equivalents			(6,328)	33,949
Cash and cash equivalents at beginning of period			30,312	19,986
Cash and cash equivalents at end of period	23,984	53,935	23,984	53,935
Supplemental disclosures of cash flow information:
Cash paid for interest			582	172
Cash paid for income taxes			597	373
Supplemental disclosures of non-cash investing and financing activities:
Reclassification of convertible senior notes hedge and embedded conversion derivative to additional paid-in capital			42,821	0
Unrealized holding loss on available for sale investments	(828)	$ (133)	(1,098)	$ (186)
As Previously Reported
Operating activities:
Net income	1,911		5,035
Adjustments to reconcile net income to net cash provided by operating activities:
Stock-based compensation expense			6,429
Amortization of intangible assets			4,525
Depreciation and amortization			555
Amortization of investment premiums & other			1,109
Accretion and amortization on debt securities			3,453
Net changes in estimated fair value of acquisition-related contingent consideration			(780)
Deferred taxes			(92)
Changes in assets and liabilities:
Accounts receivable			(6,171)
Contract assets			345
Other assets			498
Accounts payable			2,440
Accrued payroll and related taxes			(4,693)
Deferred revenue			(3,126)
Other liabilities			159
Net cash provided by operating activities			9,686
Investing activities:
Purchases of investments			(47,818)
Sales and maturities of investments			173,316
Acquisitions, net of cash acquired			(126,607)
Purchases of property and equipment			(634)
Net cash used in investing activities			(1,743)
Financing activities:
Proceeds from the issuance of equity plan common stock			1,128
Repurchases and retirements of common stock			(14,828)
Principal payments on other borrowings			(36)
Net cash provided by (used in) financing activities			(13,736)
Foreign currency effect on cash and cash equivalents			(535)
Net increase (decrease) in cash and cash equivalents			(6,328)
Cash and cash equivalents at beginning of period			30,312
Cash and cash equivalents at end of period	23,984		23,984
Supplemental disclosures of cash flow information:
Cash paid for interest			582
Cash paid for income taxes			597
Supplemental disclosures of non-cash investing and financing activities:
Reclassification of convertible senior notes hedge and embedded conversion derivative to additional paid-in capital			42,821
Unrealized holding loss on available for sale investments	(828)		(1,098)
Total Adjustments
Operating activities:
Net income	(898)		(898)
Adjustments to reconcile net income to net cash provided by operating activities:
Stock-based compensation expense			0
Amortization of intangible assets			0
Depreciation and amortization			0
Amortization of investment premiums & other			0
Accretion and amortization on debt securities			0
Net changes in estimated fair value of acquisition-related contingent consideration			0
Deferred taxes			(431)
Changes in assets and liabilities:
Accounts receivable			0
Contract assets			0
Other assets			0
Accounts payable			1,329
Accrued payroll and related taxes			0
Deferred revenue			0
Other liabilities			0
Net cash provided by operating activities			0
Investing activities:
Purchases of investments			0
Sales and maturities of investments			0
Acquisitions, net of cash acquired			0
Purchases of property and equipment			0
Net cash used in investing activities			0
Financing activities:
Proceeds from the issuance of equity plan common stock			0
Repurchases and retirements of common stock			0
Principal payments on other borrowings			0
Net cash provided by (used in) financing activities			0
Foreign currency effect on cash and cash equivalents			0
Net increase (decrease) in cash and cash equivalents			0
Cash and cash equivalents at beginning of period			0
Cash and cash equivalents at end of period	0		0
Supplemental disclosures of cash flow information:
Cash paid for interest			0
Cash paid for income taxes			0
Supplemental disclosures of non-cash investing and financing activities:
Reclassification of convertible senior notes hedge and embedded conversion derivative to additional paid-in capital			0
Unrealized holding loss on available for sale investments	$ 0		$ 0