v3.19.3
STOCKHOLDERS' EQUITY - Restricted Stock Awards and Restricted Stock Units Activity (Details) - RSAs and RSUs
9 Months Ended
Sep. 30, 2019
$ / shares
shares
Number of shares  
Beginning balance (in shares) | shares 17,934,728
Granted (in shares) | shares 5,735,224
Vested (in shares) | shares (6,016,950)
Forfeited (in shares) | shares (1,727,904)
Ending balance (in shares) | shares 15,925,098
Weighted Average Grant Date Fair Value  
Beginning balance (in USD per share) | $ / shares $ 31.34
Granted (in USD per share) | $ / shares 73.29
Vested (in USD per share) | $ / shares 29.05
Forfeited (in USD per share) | $ / shares 35.90
Ending balance (in USD per share) | $ / shares $ 46.82