Summary of Significant Accounting Policies - Additional Information (Details) (USD $)	3 Months Ended	12 Months Ended			0 Months Ended
	Mar. 25, 2014	Dec. 31, 2014 Segment	Dec. 31, 2013	Dec. 31, 2012	Mar. 25, 2014
Summary Of Significant Accounting Policies [Line Items]
Convertible redeemable preferred stock converted into common stock	12,115,183	0			12,115,183
Common stock, shares authorized	175,000,000	175,000,000	14,700,000		175,000,000
Preferred stock, shares authorized	25,000,000	25,000,000	0		25,000,000
Accretion on preferred stock	$ 86,899,555	$ 86,899,555	$ 55,885,844	$ 3,323,000
Number of operating segments		1
Significant uncertain tax positions		0	0
Revenue		0
Expected dividend yield		0.00%
Depreciation expense		49,363	1,282	0
Minimum
Summary Of Significant Accounting Policies [Line Items]
Property, plant and equipment, Useful life		3 years
Maximum
Summary Of Significant Accounting Policies [Line Items]
Property, plant and equipment, Useful life		7 years
IPO
Summary Of Significant Accounting Policies [Line Items]
Issuance of common stock, shares					6,762,000
Sale of stock, price per share	$ 17.00				$ 17.00
Proceeds from issuance of initial public offering					$ 104,364,560
Convertible redeemable preferred stock converted into common stock	12,115,183				12,115,183
Overallotment option granted to underwriters
Summary Of Significant Accounting Policies [Line Items]
Issuance of common stock, shares					879,647