In connection with the closing of an underwritten public offering on April 12, 2017, the Company issued Series A Preferred Stock. During the year ended December 31, 2018, 3,680 shares of the Series A Preferred Stock were converted into 736,000 shares of common stock of the Company. As of December 31, 2018, there were no shares of Series A Preferred stock issued and outstanding.

On February 13, 2018, the Company entered into an underwriting agreement with JonesTrading, in connection with a registered firm commitment underwritten public offering of 2,941,176 shares of common stock, pursuant to a shelf registration statement that was declared effective by the SEC on February 6, 2018. On February 15, 2018 the Company sold 3,382,352 shares of common stock (including 441,176 shares of common stock sold pursuant to the exercise of the underwriters’ overallotment option) at a price to the public of $34.00 per share. The net proceeds to the Company, after deducting the underwriting discounts and commissions and offering expenses payable by the Company were approximately $106.8 million.

In connection with the closing of the underwritten public offering on April 12, 2017, the Company also issued warrants to purchase 2,070,000 shares of common stock at an exercise price of $5.50 per share. Upon their issuance, the common stock warrants were determined to be equity instruments under ASC 480 and ASC 815-40. The net proceeds allocated to the warrants based on a relative fair value basis resulted in $5.0 million being allocated to the warrants. As of December 31, 2019, the Company had no warrants outstanding associated with this offering.

The following is a summary of warrant activity for the year ended December 31, 2019 and 2018:

	Number of Shares			Weighted Average
	Underlying Warrants			Exercise Price
Outstanding — December 31, 2017		1,751,708		$	6.46
Issued		—
Exercised		(1,735,419	)	$	5.50
Forfeited/Cancelled⁽¹⁾		(6,095	)	$	5.50
Outstanding — December 31, 2018		10,194		$	155.73
Issued		—
Exercised		—
Forfeited/Cancelled		(2,337	)	$	499.50
Outstanding — December 31, 2019		7,857		$	53.61

(1)	In November 2018, 1,845 warrants were cancelled by Healthcare Ventures VIII, a related party.