Note 3 - Summary of Significant Accounting Policies (Details Textual) - USD ($) $ in Thousands	2 Months Ended	3 Months Ended		6 Months Ended	9 Months Ended	12 Months Ended
	Feb. 08, 2018	Feb. 28, 2018	Nov. 30, 2017	Feb. 28, 2018	May 31, 2018	Aug. 31, 2018	Aug. 31, 2017	Aug. 31, 2016	Aug. 31, 2015
Unbilled Receivables, Not Billable						$ 6,400
Allowance for Doubtful Accounts Receivable, Ending Balance						3,500	$ 2,700
Research and Development Expense, Total						217,100
Interest Income and Fees, Bankers Acceptances, Certificates of Deposit and Commercial Paper						$ 1,300	1,600	$ 1,600
Number of Reporting Units						3
Goodwill, Impairment Loss						$ 0	0
Impairment of Intangible Assets (Excluding Goodwill), Total						$ 0	0	0
Employee Compensation, Percentage of Discretionary Incentives						10.00%
Accrued Bonuses						$ 43,600	39,200
Restructuring Charges, Total						17,400
Restructuring Reserve, Employee-related Liabilities						5,600
Accumulated Other Comprehensive Income (Loss), Foreign Currency Translation Adjustment, Net of Tax, Ending Balance						(47,953)	(38,522)
Unrecognized Tax Benefits, Ending Balance						$ 9,223	$ 11,484	$ 8,782	$ 6,776
Effective Income Tax Rate Reconciliation, Share-based Compensation, Excess Tax Benefit, Amount			$ 9,500		$ 9,500
Income Tax Expense (Benefit), Continuing Operations, Transition Tax	$ 23,200	$ 23,200		$ 23,200
Income Tax Expense (Benefit), Continuing Operations, Adjustment of Deferred Tax (Asset) Liability		$ 2,300		$ 2,300
Computer Equipment [Member]
Property, Plant and Equipment, Useful Life						3 years
Furniture and Fixtures [Member]
Property, Plant and Equipment, Useful Life						7 years