8. Redeemable Convertible Preferred Stock

As of December 31, 2016, the authorized capital stock of the Company included 22,380,952 shares of $0.0001 par value preferred stock, of which 3,333,333 shares were designated as Series Seed Preferred Stock and 19,047,619 shares were designated as Series A Preferred Stock. As of December 31, 2017, the authorized capital stock of the Company included 34,972,535 shares of $0.0001 par value preferred stock, of which 3,333,333 shares were designated as Series Seed Preferred Stock and 31,639,202 shares were designated as Series A Preferred Stock.

In January 2016, the Company issued and sold 3,333,333 shares of Series Seed Preferred Stock at a price of $0.45 per share, for total proceeds of $1,398, net of issuance costs of $102.

In July 2016, the Company issued and sold 5,714,286 shares of Series A Preferred Stock, at a price of $1.3125 per share, for total proceeds of $7,297, net of issuance costs of $203. The terms of the Series A Preferred Stock Purchase Agreement included the obligation of the investors to purchase, and the Company to sell, up to 13,333,333 additional shares of Series A Preferred Stock at $1.3125 per share contingent upon the achievement of certain specified milestones or at the election of a required vote by the investors and the Board. The Company concluded that the right to participate in the future issuance of Series A Preferred Stock did not meet the definition of a freestanding financial instrument, as the rights were not legally detachable from the Series A Preferred Stock.

In March 2017, the Company amended certain provisions of the Series A Preferred Stock. The changes included issuing additional instruments through a preferred stock dividend in the amount of 3,720,864 shares of Series A Preferred Stock, which effectively repriced the outstanding shares of Series A Preferred Stock, changing the purchase price for future shares, and decreasing the redemption price per share such that total redemption value was not affected. Concurrent with the amendment, the Company issued 4,403,070 additional shares of Series A Preferred Stock at a purchase price of $0.7949 per share, for total proceeds of $3,452, net of issuance costs of $48. Additionally, the number of shares of Series A Preferred Stock which could be issued in the future was changed to 17,612,279 shares. The Company assessed the changes to the terms and concluded that it represented a material change to substantive terms of the instrument, and therefore represented, for accounting purposes, an extinguishment and re-issuance of the Series A Preferred Stock outstanding at the time. As the carrying value of the outstanding shares of Series A Preferred Stock prior to the extinguishment was deemed to equal the aggregate fair value of the reissued shares and the shares issued as a dividend, no gain or loss was recognized on extinguishment of the Series A Preferred Stock.

In October 2017, the Company issued and sold an additional 17,612,279 shares of Series A Preferred Stock, at a price of $0.7949 per share, for total proceeds of $13,963, net of issuance costs of $37.

Prior to the IPO, the authorized capital stock of the Company included 63,491,857 shares of $0.0001 par value preferred stock, of which 3,333,333 shares have been designated as Series Seed Preferred Stock, 31,639,202 shares have been designated as Series A Preferred Stock and 28,519,322 shares have been designated as Series B Preferred Stock.

On January 19, 2018, the Company entered into a stock purchase agreement for the sale of 28,285,557 shares of Series B Preferred Stock for $2.1389 per share. The total gross proceeds received were $60,500 and issuance costs were $2,243. In addition, the Company issued 233,765 shares of Series B Preferred Stock to BioMarin as required by the Company’s license agreement with BioMarin (Note 11).

As of December 31, 2017, the Preferred Stock consisted of the following:


	December 31, 2017
	Preferred Shares Authorize		Preferred Shares Issued and Outstanding		Carrying Value		Liquidation Preference		Common Stock Issuable Upon Conversion
Series Seed preferred stock		3,333,333		3,333,333	$	1,500,000	$	1,500,000		806,711
Series A preferred stock		31,639,202		31,450,499		25,000,000		25,000,000		7,611,438

		34,972,535		34,783,832	$	26,500,000	$	26,500,000		8,418,149

Upon closing of the IPO, the Preferred Stock as of December 31, 2017, together with Series B Preferred Stock issued in January 2018, were converted to 15,320,213 shares of common stock. The holders of the Company’s Preferred Stock had certain voting, dividend, and redemption rights, as well as liquidation preferences and conversion privileges. All rights, preferences, and privileges associated with the preferred stock were terminated at the time of the Company’s IPO in conjunction with the conversion of all outstanding shares of Preferred Stock into shares of common stock.