Subsequent Events	3 Months Ended
Mar. 31, 2019
Subsequent Events [Abstract]
SUBSEQUENT EVENTS	11. SUBSEQUENT EVENTS On April 1, 2019, the Company filed a Registration Statement on Form S-3 (the “Shelf”) with the SEC in relation to the registration of common stock, preferred stock, debt securities, warrants and/or units of any combination thereof in the aggregate amount of up to $350.0 million for a period up to three years from the date of the filing. The Company also simultaneously entered into a sales agreement with a sales agent providing for the offering, issuance and sale by the Company of up to an aggregate $100.0 million of its common stock from time to time in “at-the-market” offerings under the Shelf. On April 12, 2019, pursuant to the Shelf, the Company completed a follow-on offering of its common stock. The Company sold 5,555,556 shares of its common stock at a public offering price of $22.50 per share and received net proceeds of $117.5 million, after deducting underwriting discounts and commissions. In addition, on April 26, 2019 and May 7, 2019, in connection with the exercise in full of the underwriters’ option to purchase additional shares, the Company issued an aggregate of 833,333 shares of its common stock at a public offering price of $22.50 per share and received net proceeds of $17.6 million, after deducting underwriting discounts and commissions.

Subsequent Events

3 Months Ended

Mar. 31, 2019

11. SUBSEQUENT EVENTS

On April 1, 2019, the Company filed a Registration Statement on Form S-3 (the “Shelf”) with the SEC in relation to the registration of common stock, preferred stock, debt securities, warrants and/or units of any combination thereof in the aggregate amount of up to $350.0 million for a period up to three years from the date of the filing. The Company also simultaneously entered into a sales agreement with a sales agent providing for the offering, issuance and sale by the Company of up to an aggregate $100.0 million of its common stock from time to time in “at-the-market” offerings under the Shelf.

On April 12, 2019, pursuant to the Shelf, the Company completed a follow-on offering of its common stock. The Company sold 5,555,556 shares of its common stock at a public offering price of $22.50 per share and received net proceeds of $117.5 million, after deducting underwriting discounts and commissions. In addition, on April 26, 2019 and May 7, 2019, in connection with the exercise in full of the underwriters’ option to purchase additional shares, the Company issued an aggregate of 833,333 shares of its common stock at a public offering price of $22.50 per share and received net proceeds of $17.6 million, after deducting underwriting discounts and commissions.