General (Details Textual)			3 Months Ended		9 Months Ended		12 Months Ended
	Feb. 08, 2021	Aug. 21, 2020 USD ($)	Sep. 30, 2021 USD ($) subsidiary $ / shares	Sep. 30, 2020 USD ($)	Sep. 30, 2021 USD ($) subsidiary $ / shares shares	Sep. 30, 2020 USD ($) shares	Dec. 31, 2020 USD ($) $ / shares	Mar. 15, 2021 $ / shares	May 11, 2020 USD ($)
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Operations commenced date					Jan. 01, 2005
Subsidiary or equity method investee, number | subsidiary			12		12
Stock split, conversion ratio	3
Common stock, par value (in dollars per share) | $ / shares			$ 0.001		$ 0.001		$ 0.001	$ 0.001
Deferred revenue, revenue recognized					$ 86,329,000
Sales returns					$ 0		$ 0
Capitalized contract cost, amortization period (years)			4 years		4 years
Gain (loss) related to the effective portion of the cash flow hedges			$ 2,663,000	$ (2,144,000)	$ 7,448,000	$ (4,919,000)
Derivative instruments not designated as hedging instruments, gain (loss), net			371,000	(876,000)	905,000	(244,000)
Income tax expense (benefit)			1,525,000	220,000	2,999,000	$ 817,000
Additional paid-in capital			(976,995,000)		(976,995,000)		$ (395,347,000)
Pro Forma
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Additional paid-in capital			31,779,000		31,779,000
Liabilities			31,779,000		$ 31,779,000
Restricted Stock Units and Stock Options
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Antidilutive securities excluded from computation of Earnings Per Share, amount (in shares) | shares					7,843,510	9,632,790
Foreign Exchange Contract
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Gain (loss) related to the effective portion of the cash flow hedges			$ 439,000	$ 128,000	$ 1,396,000	$ (176,000)
Maintenance
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Revenue, performance obligation, description of timing					one year
Revolving Credit Facility | Line of Credit
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Debt instrument, term		3 years
Line of credit facility, maximum borrowing capacity		$ 70,000,000
Line of credit facility, accordion feature, increase limit		90,000,000
Letter of Credit | Line of Credit
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Line of credit facility, maximum borrowing capacity		$ 15,000,000
2025 Senior Notes | Convertible Debt Securities
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Antidilutive securities excluded from computation of Earnings Per Share, amount (in shares) | shares					8,239,254
2025 Senior Notes | Convertible Debt
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Interest rate, stated percentage									1.25%
Principal amount									$ 253,000
Initial conversion price (in dollars per share) | $ / shares			$ 30.71		$ 30.71