Employee Stock-Based Compensation - Stock Option Supplemental Information (Details) (USD $) In Thousands, except Share data, unless otherwise specified	Sep. 30, 2014 Y
Options Outstanding
Number of Options	5,600,433
Weighted Average Remaining Contractual Term (in years)	8.15
Weighted Average Exercise Price	$ 5.01
Weighted Average Fair Value	$ 3.85
Aggregate intrinsic value (in thousands)	$ 92,000
Options Exercisable
Number of Options	1,756,885
Weighted Average Remaining Contractual Term (in years)	7.72
Weighted Average Exercise Price	$ 2.26
Weighted Average Fair Value	$ 1.52
Aggregate intrinsic value (in thousands)	$ 34,000