8.	Stockholders’ Equity Common Stock

On July 1, 2015, the Company completed an IPO, and issued and sold 8,545,138 shares of common stock at a public offering price of $18.00 per share, resulting in net proceeds of approximately $139,267 after deducting underwriting discounts and commissions and other offering expenses totaling $3,748. The shares issued upon closing of the IPO included 1,114,583 shares of the Company’s common stock, which were sold to the underwriters pursuant to the full exercise of their option to purchase additional shares of common stock. Upon the listing of the Company’s common stock on the NASDAQ on June 26, 2015, all outstanding shares of the Company’s convertible preferred stock automatically converted into 22,866,987 shares of the Company’s common stock.

As of December 31, 2014, the Company’s Amended and Restated Certificate of Incorporation, as further amended, authorized the Company to issue 38,000,000 shares of common stock, $0.001 par value per share. On July 1, 2015, in connection with the closing of the IPO, the Company effected its Restated Certificate of Incorporation, which authorizes the Company to issue 200,000,000 shares of common stock, $0.001 par value per share.

Stock Options

The following table summarizes the Company’s stock option activity since December 31, 2015:

	Number of Shares			Weighted Average Exercise Price		Weighted Average Remaining Contractual Term		Aggregate Intrinsic Value
						(in years)
Outstanding as of December 31, 2015		5,026,246		$	8.01		8.70	$	136,945
Granted		992,625			27.52
Exercised		(136,685	)		1.15
Forfeited		—			—
Outstanding as of March 31, 2016		5,882,186		$	11.46		8.68	$	93,314
Options exercisable as of March 31, 2016		1,892,915		$	2.66		8.05	$	45,250
Options vested and expected to vest as of March 31, 2016		5,756,568		$	11.34		8.67	$	91,974

The weighted average grant-date fair value of stock options granted during the three months ended March 31, 2016 was $19.59.

Stock-based Compensation Expense

The Company recorded stock-based compensation expense related to stock options and restricted common stock in the following expense categories of its consolidated statements of operations and comprehensive loss:

	Three Months Ended March 31,
	2016		2015
Research and development expenses	$	2,186	$	623
General and administrative expenses		1,718		704
	$	3,904	$	1,327