Description of Business and Summary of Significant Accounting Policies - Additional Information (Detail)	3 Months Ended		6 Months Ended		12 Months Ended	103 Months Ended
	Sep. 30, 2016 Customer	Sep. 30, 2015 Customer	Sep. 30, 2016 USD ($) Customer	Sep. 30, 2015 Customer	Mar. 31, 2016 USD ($) Customer	Sep. 30, 2016 USD ($)
Description Of Business And Summary Of Significant Accounting Policies [Line Items]
Entity incorporation, state name	Delaware
Company incorporation date	Feb. 20, 2008
Other-than-temporary impaired investments | $			$ 0		$ 0
Goodwill impairment | $						$ 0
Accounts Receivable
Description Of Business And Summary Of Significant Accounting Policies [Line Items]
Number of customers | Customer			0		0
Accounts Receivable | Credit Concentration Risk
Description Of Business And Summary Of Significant Accounting Policies [Line Items]
Concentration of risk, percentage			10.00%		10.00%
Revenue
Description Of Business And Summary Of Significant Accounting Policies [Line Items]
Number of customers | Customer	0	0	0	0
Revenue | Credit Concentration Risk
Description Of Business And Summary Of Significant Accounting Policies [Line Items]
Concentration of risk, percentage	10.00%	10.00%	10.00%	10.00%