Annual report pursuant to Section 13 and 15(d)

Stock Plans (Details 2)

v3.3.1.900
Stock Plans (Details 2) - USD ($)
$ in Thousands
12 Months Ended
Dec. 31, 2015
Dec. 31, 2014
Dec. 31, 2013
Share-based Goods and Nonemployee Services Transaction [Line Items]      
Weighted-average risk-free interest rate 1.88% 2.04% 0.92%
Expected dividend payments $ 0 $ 0 $ 0
Expected holding period (years) [1] 6 years 5 months 23 days 6 years 5 months 16 days 3 years 10 months 24 days
Weighted-average volatility factor [2] 1.16% 1.65% 1.38%
Estimated forfeiture rates for options granted 30.00% 31.00% 31.00%
[1] Expected holding period is based on historical experience of similar awards, giving consideration to the contractual terms of the stock-based awards, vesting schedules and the expectations of future employee behavior.
[2] Weighted average volatility is based on the historical volatility of our common stock.