Quarterly report pursuant to Section 13 or 15(d)

Equity Incentive Plans - Summary of Employee and Nonemployee Stock Option Activity (Detail)

v2.4.1.9
Equity Incentive Plans - Summary of Employee and Nonemployee Stock Option Activity (Detail) (USD $)
3 Months Ended 12 Months Ended
Mar. 31, 2015
Dec. 31, 2014
Options Outstanding, Number of Shares Outstanding    
Outstanding, beginning balance 1,839,458us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingNumber  
Granted 97,000us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrantsInPeriodGross  
Cancelled or expired (48,083)us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsForfeituresAndExpirationsInPeriod  
Outstanding, ending balance 1,888,375us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingNumber 1,839,458us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingNumber
Exercisable 739,928us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExercisableNumber  
Options Outstanding, Weighted-Average Exercise Price    
Outstanding, beginning balance $ 10.58us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingWeightedAverageExercisePrice  
Granted $ 9.18us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardOptionsGrantsInPeriodWeightedAverageExercisePrice  
Cancelled or expired $ 10.74us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsForfeituresAndExpirationsInPeriodWeightedAverageExercisePrice  
Outstanding, ending balance $ 10.50us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingWeightedAverageExercisePrice $ 10.58us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingWeightedAverageExercisePrice
Exercisable $ 9.57us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExercisableWeightedAverageExercisePrice  
Weighted-Average Remaining Contractual Term (in years)    
Outstanding 8 years 3 months 18 days 8 years 5 months 27 days
Exercisable 6 years 9 months 15 days  
Aggregate Intrinsic Value    
Outstanding, beginning balance $ 618,250us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingIntrinsicValue  
Outstanding, ending balance 1,325,605us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingIntrinsicValue 618,250us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingIntrinsicValue
Exercisable $ 806,090us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardOptionsExercisableIntrinsicValue1