Subsequent Event

12 Months Ended

Dec. 31, 2017

Subsequent Events [Abstract]

Subsequent Event

13. Subsequent Event

On February 13, 2018, the Company completed the sale of 4,032,012 shares of its common stock at a price to the public of $164.00 per share, resulting in net proceeds to the Company of $631.1 million, after deducting underwriting discounts and commissions and estimated offering expenses payable by the Company.