Business Combinations (Narrative) (Details) - USD ($)				3 Months Ended		6 Months Ended
	Dec. 02, 2014	Oct. 01, 2014	May. 13, 2014	May. 31, 2015	May. 31, 2014	May. 31, 2015	May. 31, 2014	Nov. 30, 2014
Business Acquisition [Line Items]
Goodwill				$ 370,533,000		$ 370,533,000		$ 232,836,000
Stock-based compensation expense				6,439,000	$ 5,709,000	12,275,000	$ 11,254,000
Acquisition-related costs				1,010,000	1,630,000	2,518,000	2,576,000
Revenues				88,817,000	80,827,000	170,198,000	155,365,000
(Loss) income before provision for income taxes				3,760,000	(20,151,000)	14,014,000	(34,159,000)
Intangible assets, amortization expense				7,300,000	700,000	$ 15,100,000	1,400,000
Telerik AD [Member]
Business Acquisition [Line Items]
Total purchase consideration	$ 262,500,000
Total consideration paid to founders and key employees in restricted stock units	$ 10,500,000
Percent of total consideration deposited into escrow	10.00%
Measurement period	1 year
Acquired intangible assets	$ 123,100,000
Deferred revenue, period for recognition	12 months
Goodwill	$ 137,921,000
Award vesting period						2 years
Stock-based compensation expense				700,000		$ 1,400,000
Acquisition-related costs				1,100,000		1,900,000
Earn-out provision	2,500,000
Expense recognized related to contingent earn-out provisions				600,000		1,200,000
Revenues				9,200,000		13,700,000
(Loss) income before provision for income taxes				7,800,000		18,700,000
Intangible assets, amortization expense						12,300,000
Pro forma amortization adjustment							$ 123,100,000
Pro forma adjustments, statutory tax rate, Bulgaria (as a percent)							10.00%
Pro forma adjustments, statutory tax rate, United States (as a percent)							37.00%
Net assets acquired	251,953,000
BravePoint Inc. [Member]
Business Acquisition [Line Items]
Total purchase consideration		$ 12,000,000
Goodwill		$ 2,257,000
Acquisition-related costs					$ 600,000	900,000
Equity interests acquired		100.00%
Net assets acquired		$ 12,000,000
Modulus [Member]
Business Acquisition [Line Items]
Total purchase consideration			$ 15,000,000
Goodwill			$ 6,433,000
Equity interests acquired			100.00%
Purchase consideration, cash			$ 12,500,000
Purchase consideration, contingent consideration			$ 2,500,000
Expected payout period			2 years
Fair value of contingent liabilities			$ 1,500,000
Net assets acquired			$ 13,950,000
Change in fair value of contingent consideration				$ 1,100,000		$ 1,200,000
Credit Agreement [Member]
Business Acquisition [Line Items]
Term loan	150,000,000
Existing Technology [Member] | Telerik AD [Member]
Business Acquisition [Line Items]
Acquired intangible assets	64,800,000
Customer Relationships [Member] | Telerik AD [Member]
Business Acquisition [Line Items]
Acquired intangible assets	47,100,000
Customer Relationships [Member] | BravePoint Inc. [Member]
Business Acquisition [Line Items]
Acquired intangible assets		$ 4,110,000
Trademarks and Trade Names [Member] | Telerik AD [Member]
Business Acquisition [Line Items]
Acquired intangible assets	$ 11,200,000