Subsequent Event - Additional Information (Detail) (USD $)	3 Months Ended	0 Months Ended
	Mar. 31, 2015	May 04, 2015
Subsequent Event [Line Items]
Options, grant date price	$ 4.10
Subsequent Event [Member] | Amended And Restated Equity Incentive Plan [Member]
Subsequent Event [Line Items]
Number of additional shares authorized for issuance		2,500,000
Aggregate number of shares available for issuance		9,500,000
Subsequent Event [Member] | Amended And Restated Equity Incentive Plan [Member] | 2015 [Member]
Subsequent Event [Line Items]
stock option compensation expense		1,200,000
Subsequent Event [Member] | Amended And Restated Equity Incentive Plan [Member] | 2016 [Member]
Subsequent Event [Line Items]
stock option compensation expense		1,200,000
Subsequent Event [Member] | Amended And Restated Equity Incentive Plan [Member] | 2017 [Member]
Subsequent Event [Line Items]
stock option compensation expense		500,000
Subsequent Event [Member] | Amended And Restated Equity Incentive Plan [Member] | 2018 [Member]
Subsequent Event [Line Items]
stock option compensation expense		100,000
Subsequent Event [Member] | Amended And Restated Equity Incentive Plan [Member] | Certain Executives And Key Employees [Member]
Subsequent Event [Line Items]
Options, grant date price		4.78
Options, weighted average fair market value		1.80
Options, number granted		1,645,000
Options granted, fair market value		2,961,000