v3.5.0.2
Stock-Based Compensation - ESPP (Details) - USD ($)
$ in Thousands
3 Months Ended 9 Months Ended
Sep. 30, 2016
Sep. 30, 2016
Sep. 30, 2015
Sep. 30, 2016
Sep. 30, 2015
Stock-Based Compensation          
Stock-based compensation expense   $ 656 $ 116 $ 1,048 $ 251
ESPP          
Stock-Based Compensation          
Maximum annual increase in shares available for issuance (in shares) 800,000 800,000   800,000  
Maximum annual increase in shares available for issuance, percentage of outstanding shares 1.00% 1.00%   1.00%  
Maximum employee payroll deduction (as a percent) 100.00% 100.00%   100.00%  
Maximum offering period       2 years  
Period between purchases       6 months  
Price of ESPP shares as percentage of market price       85.00%  
Holding period for purchases after the first offering period       6 months  
Holding period for purchases during the first offering period       12 months  
Stock-based compensation expense   $ 200   $ 200  
Weighted-average assumptions used to estimate the fair value of ESPP shares          
Expected term (years) 1 year 3 months 18 days        
Volatility (as a percent) 51.18%        
Risk-free interest rate (as a percent) 0.61%        
ESPP | Class A common stock          
Stock-Based Compensation          
Stock available for issuance (in shares) 800,000 800,000   800,000