Stock-Based Compensation (Narrative) (Details) $ / shares in Units, $ in Millions	12 Months Ended
	Nov. 30, 2017 USD ($) period plan $ / shares Executives shares	Nov. 30, 2016 USD ($) $ / shares Executives shares	Nov. 30, 2015 USD ($) $ / shares Executives shares
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of shareholder approved stock plans | plan	1
Number of plans for which shareholder approval not required | plan	2
Closing stock price on November 30, 2016 (in dollars per share) | $ / shares	$ 41.34
Unrecognized stock-based compensation expense, net of expected forfeitures | $	$ 24.5
Costs are expected to be recognized, weighted average period	2 years 2 months 19 days
Number of executives whose employment was terminated | Executives	3	2	3
Additional stock-based compensation expenses related to separation and acceleration vesting | $	$ 1.5	$ 0.3	$ 0.3
2008 Stock Option And Incentive Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares issuable under stock plans (in shares)	54,510,000
Shares available for grant under stock plans (in shares)	3,129,512
2002 Nonqualified Stock Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares issuable under stock plans (in shares)	9,750,000
Shares available for grant under stock plans (in shares)	906,293
2004 Inducement Stock Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares issuable under stock plans (in shares)	1,500,000
Shares available for grant under stock plans (in shares)	583,021
Employee Stock Purchase Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares issuable under stock plans (in shares)	9,450,000
ESPP offering period	27 months
ESPP number of purchase periods | period	9
ESPP purchase price (as a percent)	85.00%
Employee stock purchase plan, issued shares (in shares)	220,000	266,000	226,000
Weighted average purchase price of shares (in dollars per share) | $ / shares	$ 22.27	$ 20.01	$ 19.58
Shares available and reserved for issuance (in shares)	815,000
Weighted average estimated fair value of options granted, per share (in dollars per share) | $ / shares	$ 8.32	$ 7.43	$ 6.89
General and administrative [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Additional stock-based compensation expenses related to separation and acceleration vesting | $			$ 0.2
Sales and marketing [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Additional stock-based compensation expenses related to separation and acceleration vesting | $	$ 0.8	$ 0.2	$ 0.1
Product development [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Additional stock-based compensation expenses related to separation and acceleration vesting | $	$ 0.7	$ 0.1
Stock Options [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting period	1 year
Weighted average estimated fair value of options granted, per share (in dollars per share) | $ / shares	$ 5.95	$ 0.00	$ 6.79
Restricted Stock Units (RSUs) [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting period	3 years
Number of common stock shares each restricted stock unit represents (in shares)	1
Stock-based compensation service period	3 years	3 years