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Income Taxes - Additional Information (Detail) (USD $)	3 Months Ended
Income Taxes - Additional Information (Detail) (USD $)	Mar. 31, 2015	Sep. 30, 2014	Mar. 31, 2014	Dec. 31, 2014
Schedule Of Income Tax [Line Items]
Valuation allowance resulting in income tax benefit	$ 3,441,000		$ 13,725,000	$ 5,618,000
Net deferred tax assets	6,040,000us-gaap_DeferredTaxAssetsLiabilitiesNet			9,490,000us-gaap_DeferredTaxAssetsLiabilitiesNet
Unrecognized stock-based compensation	133,585,000			101,108,000
NOLs deemed worthless	3,487,000
Deferred tax asset related to NOLs	0us-gaap_DeferredTaxAssetsNet
Income tax expense/(benefit)	8,958,000us-gaap_IncomeTaxExpenseBenefit		(13,725,000)us-gaap_IncomeTaxExpenseBenefit
Gross deferred tax asset	3,450,000us-gaap_DeferredTaxAssetsGross
Credit to additional paid-in capital for the amount of NOLs from stock-based compensation	5,158,000
State income taxes	350,000
Income tax rate	38.38%	38.00%
Foreign Subsidiaries [Member]
Schedule Of Income Tax [Line Items]
Deferred tax asset offset by a valuation allowance	$ 1,105,000		$ 816,000
Previously Reported [Member]
Schedule Of Income Tax [Line Items]
Income tax rate		45.00%