Stock-Based Compensation - Allocation of Stock-Based Compensation Expense, ESPP (Details) - 2015 Employee Stock Purchase Plan
$ in Thousands
12 Months Ended
Dec. 31, 2015
USD ($)
ESPP stock-based compensation expense by statement of operations line item  
Stock-based compensation expense $ 504
Other cost of revenue  
ESPP stock-based compensation expense by statement of operations line item  
Stock-based compensation expense 17
Sales and marketing  
ESPP stock-based compensation expense by statement of operations line item  
Stock-based compensation expense 177
Research and development  
ESPP stock-based compensation expense by statement of operations line item  
Stock-based compensation expense 244
General and administrative  
ESPP stock-based compensation expense by statement of operations line item  
Stock-based compensation expense $ 66