Annual report pursuant to Section 13 and 15(d)

Stock-Based Compensation - Black-Scholes-Merton Option Pricing Model (Details)

v2.4.1.9
Stock-Based Compensation - Black-Scholes-Merton Option Pricing Model (Details)
12 Months Ended
Dec. 31, 2014
Dec. 31, 2013
Employee Stock Option    
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]    
Weighted-average risk-free interest rate 1.85%us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsRiskFreeInterestRate
/ us-gaap_AwardTypeAxis
= us-gaap_EmployeeStockOptionMember
 
Weighted-average expected life (in years) 6 years 3 months 18 days  
Expected dividend yield 0.00%us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsExpectedDividendRate
/ us-gaap_AwardTypeAxis
= us-gaap_EmployeeStockOptionMember
 
Weighted-average expected volatility 47.00%us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsWeightedAverageVolatilityRate
/ us-gaap_AwardTypeAxis
= us-gaap_EmployeeStockOptionMember
 
Stock Options to Non-employees    
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]    
Weighted-average risk-free interest rate 2.52%us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsRiskFreeInterestRate
/ us-gaap_AwardTypeAxis
= us-gaap_StockCompensationPlanMember
2.74%us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsRiskFreeInterestRate
/ us-gaap_AwardTypeAxis
= us-gaap_StockCompensationPlanMember
Weighted-average expected life (in years) 9 years 8 months 12 days 10 years
Expected dividend yield 0.00%us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsExpectedDividendRate
/ us-gaap_AwardTypeAxis
= us-gaap_StockCompensationPlanMember
0.00%us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsExpectedDividendRate
/ us-gaap_AwardTypeAxis
= us-gaap_StockCompensationPlanMember
Weighted-average expected volatility 44.00%us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsWeightedAverageVolatilityRate
/ us-gaap_AwardTypeAxis
= us-gaap_StockCompensationPlanMember
52.00%us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsWeightedAverageVolatilityRate
/ us-gaap_AwardTypeAxis
= us-gaap_StockCompensationPlanMember