Fair Value Measurements - Fair Value Measurements of Using Significant Unobservable Level 3 Inputs (Detail)	12 Months Ended
	Dec. 31, 2013 USD ($)
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Changes in fair value reflected as other financing expense	$ 3,457,184
Convertible promissory notes [Member]
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Beginning balance	0
Issuance of securities	970,000
Accretion of debt discount to interest expense	31,439
Conversion to equity at IPO	(1,001,439)
Ending balance	0
Preferred stock warrant liability [Member]
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Beginning balance	160,345
Issuance of securities	625,679
Changes in fair value reflected as other financing expense	3,457,184
Conversion to equity at IPO	(4,243,208)
Ending balance	$ 0