Summary of Significant Accounting Policies (Details 4) (USD $)	0 Months Ended	3 Months Ended
	Nov. 13, 2012	Sep. 30, 2013 item	Sep. 30, 2012
Additional disclosure for options
Cash received for exercise of stock options		$ 4,025,000	$ 688,000
Financial Instruments and Concentration of Credit Risk
Number of financial institutions in the U.S. in which cash and cash equivalents are primarily maintained		3
2006 Plan
Stock-Based Compensation
Stock compensation expense		4,700,000	3,800,000
Number of employee share-based compensation plans		1
Additional number of shares authorized for issuance	3,500,000
Common stock authorized for issuance (in shares)	12,000,000
Additional disclosure for options
Estimated fair value of unvested employee awards, net of estimated forfeitures		28,500,000
Weighted average vesting period of unvested employee awards		2 years 6 months
2006 Plan | Maximum
Stock-Based Compensation
Number of shares of common stock added to the Plan from the Former Plan		5,900,000
2006 Plan | Stock options
Weighted-average assumptions used to estimate the fair value of each stock option
Number of group of awards for which expected term is calculated for and applied		1
Dividend (as a percent)		0.00%	0.00%
Volatility (as a percent)		60.44%	60.44%
Risk-free interest rate (as a percent)		1.69%	0.84%
Expected life		6 years 3 months 18 days	6 years 3 months 18 days
Weighted-average grant date fair values of options granted (in dollars per share)		$ 10.93	$ 8.91
Additional disclosure for options
Exercised (in shares)		545,000
Cash received for exercise of stock options		$ 4,000,000
2006 Plan | Stock options | Maximum
Stock-Based Compensation
Vesting period		4 years
Exercise period		10 years
Additional disclosure for options
Exercised (in dollars per share)		$ 15.83
2006 Plan | Stock options | Minimum
Additional disclosure for options
Exercised (in dollars per share)		$ 3.19