Quarterly report pursuant to Section 13 or 15(d)

Stockholders' Equity - Summary of Restricted Stock Activity (Details)

v3.8.0.1
Stockholders' Equity - Summary of Restricted Stock Activity (Details)
3 Months Ended
Mar. 31, 2018
$ / shares
shares
Time based restricted stock units  
Class Of Stock [Line Items]  
Unvested restricted stock units/ awards outstanding, Beginning balance 42,028
Granted 20,049
Vested (1,836)
Forfeited/canceled (546)
Unvested restricted stock units/ awards outstanding, Ending balance 59,695
Performance and time based restricted stock units  
Class Of Stock [Line Items]  
Unvested restricted stock units/ awards outstanding, Beginning balance 13,109
Vested (4,370)
Unvested restricted stock units/ awards outstanding, Ending balance 8,739
Restricted stock units  
Class Of Stock [Line Items]  
Unvested restricted stock units/ awards outstanding, Beginning balance 55,137
Granted 20,049
Vested (6,206)
Forfeited/canceled (546)
Unvested restricted stock units/ awards outstanding, Ending balance 68,434
Unvested and expected to vest restricted stock units/awards outstanding 63,143
Weighted-average grant date fair value per share, Unvested restricted stock units/ awards outstanding, Beginning balance | $ / shares $ 90.05
Weighted-average grant date fair value per share, Granted | $ / shares 122.00
Weighted-average grant date fair value per share, Vested | $ / shares 87.38
Weighted-average grant date fair value per share, Forfeited/canceled | $ / shares 91.52
Weighted-average grant date fair value per share, Unvested restricted stock units/ awards outstanding, Ending balance | $ / shares 99.64
Weighted-average grant date fair value per share, Unvested and expected to vest restricted stock units/awards outstanding | $ / shares $ 99.79
Time based restricted stock awards  
Class Of Stock [Line Items]  
Unvested restricted stock units/ awards outstanding, Beginning balance 20,789
Granted 21,222
Unvested restricted stock units/ awards outstanding, Ending balance 42,011
Performance and time based restricted stock awards  
Class Of Stock [Line Items]  
Unvested restricted stock units/ awards outstanding, Beginning balance 20,785
Granted 31,830
Vested (6,928)
Unvested restricted stock units/ awards outstanding, Ending balance 45,687
Restricted stock awards  
Class Of Stock [Line Items]  
Unvested restricted stock units/ awards outstanding, Beginning balance 41,574
Granted 53,052
Vested (6,928)
Unvested restricted stock units/ awards outstanding, Ending balance 87,698
Unvested and expected to vest restricted stock units/awards outstanding 67,432
Weighted-average grant date fair value per share, Unvested restricted stock units/ awards outstanding, Beginning balance | $ / shares $ 91.52
Weighted-average grant date fair value per share, Granted | $ / shares 122.00
Weighted-average grant date fair value per share, Vested | $ / shares 91.52
Weighted-average grant date fair value per share, Unvested restricted stock units/ awards outstanding, Ending balance | $ / shares 108.30
Weighted-average grant date fair value per share, Unvested and expected to vest restricted stock units/awards outstanding | $ / shares $ 108.07