Stockholders' Equity

3 Months Ended

Mar. 31, 2019

Stockholders Equity Note [Abstract]

Stockholders' Equity

8. Stockholders’ Equity

On March 8, 2018, the Company filed the 2018 Shelf Registration Statement covering the potential offering, issuance, and sale of an indeterminate amount of common stock, preferred stock, debt securities, warrants and/or units. In March 2019, the Company completed a follow-on offering under the 2018 Shelf Registration Statement pursuant to which the Company issued 5,663,750shares of common stock at a price of $51.00per share, which included 738,750 shares sold directly to the underwriters upon exercise of their over-allotment option. During the three months ended March 31, 2019, the Company received proceeds totaling approximately $271.2 million from the offering, net of underwriting discounts and commissions and offering expenses.

Common Stock Reserved for Issuance

The Company has reserved shares of common stock for issuance as follows:

	March 31, 2019		December 31, 2018
Options and awards issued and outstanding		5,257,140		3,864,407
Shares available for issuance under 2015 Stock Option and Incentive Plan		1,077,783		904,785
Shares available for issuance under 2015 Employee Stock Purchase Plan		1,183,605		780,716
Total		7,518,528		5,549,908