Employee Equity Incentive Plans (Details) (USD $)	6 Months Ended
	Mar. 31, 2013
Summary of stock options outstanding and changes
Number of Shares, Outstanding Beginning Balance	8,142,468
Weighted Average Exercise Price, Beginning Balance	$ 2.67
Number of Shares, Granted	1,859,107
Weighted Average Exercise Price per Share, Granted	$ 2.64
Number of Shares, Exercised	(389,781)
Weighted Average Exercise Price per Share, Exercised	$ 1.39
Number of Shares, Forfeited	(187,091)
Weighted Average Exercise Price per Share, Forfeited	$ 3.37
Number of Shares, Outstanding Ending Balance	9,424,703
Weighted Average Exercise Price, Ending Balance	$ 2.71
Options Outstanding, Weighted Average Remaining Contractual Term	7 years 7 months 6 days
Aggregate Intrinsic Value, Outstanding	$ 5,313,772
Number of Shares, Vested and expected to vest in the future	9,072,526
Weighted Average Exercise Price per Share, Vested and expected to vest in the future	$ 2.71
Weighted Average Remaining Contractual Term, Vested and expected to vest in the future	7 years 6 months
Aggregate Intrinsic Value, Vested and expected to vest in the future	5,218,502
Options Exercisable, Number of Shares	4,346,368
Options Exercisable, Weighted Average Exercise Price	$ 2.68
Weighted Average Remaining Contractual Term, Exercisable	6 years 6 months
Aggregate Intrinsic Value, Exercisable	$ 3,696,086