Description of Business and Summary of Significant Accounting Policies - Additional Information (Detail)	1 Months Ended		3 Months Ended			12 Months Ended	88 Months Ended
	Jun. 30, 2015 shares	Dec. 31, 2014 USD ($) $ / shares shares	Jun. 30, 2015 USD ($) Customer	Mar. 31, 2015 Customer	Jun. 30, 2014 Customer	Mar. 31, 2015 USD ($)	Jun. 30, 2015 USD ($)
Description Of Business And Summary Of Significant Accounting Policies [Line Items]
Company incorporation date			Feb. 20, 2008
Entity Incorporation, State Name			Delaware
Other-than-temporarily impaired investments | $			$ 0			$ 0
Goodwill impairment | $							$ 0
Common Stock [Member]
Description Of Business And Summary Of Significant Accounting Policies [Line Items]
Number of common stock shares issued upon conversion of convertible preferred stock	24,885,778	24,885,778
Series F Convertible Preferred Stock [Member]
Description Of Business And Summary Of Significant Accounting Policies [Line Items]
Convertible preferred stock conversion rate		1.02
Series A Through E Preferred Stock [Member]
Description Of Business And Summary Of Significant Accounting Policies [Line Items]
Convertible preferred stock conversion rate		1
Convertible Preferred Stock [Member]
Description Of Business And Summary Of Significant Accounting Policies [Line Items]
Number of convertible preferred stock shares converted		24,813,343
Initial Public Offering [Member]
Description Of Business And Summary Of Significant Accounting Policies [Line Items]
Common stock shares issued		5,750,000
Proceeds from sale of common stock, net of underwriters' discounts and commissions | $		$ 123,000,000
Common stock shares issued, price per share | $ / shares		$ 23.00
Offering expenses | $		$ 3,100,000
Accounts Receivable [Member]
Description Of Business And Summary Of Significant Accounting Policies [Line Items]
Number of customers | Customer			1	1
Revenue [Member]
Description Of Business And Summary Of Significant Accounting Policies [Line Items]
Number of customers | Customer			0		0
Credit Concentration Risk [Member] | Accounts Receivable [Member]
Description Of Business And Summary Of Significant Accounting Policies [Line Items]
Concentration of risk, percentage			16.00%	12.00%
Credit Concentration Risk [Member] | Revenue [Member]
Description Of Business And Summary Of Significant Accounting Policies [Line Items]
Concentration of risk, percentage			10.00%		10.00%