Warrants to Purchase Convertible Preferred Stock	9 Months Ended
Sep. 30, 2019
Warrants to Purchase Convertible Preferred Stock.
Warrants to Purchase Convertible Preferred Stock	8. Warrants to Purchase Convertible Preferred Stock During 2015 and 2017, the Company issued warrants to purchase up to 133,333 shares of Series A Preferred Stock and 2,234 shares of Series B Preferred Stock, respectively, in connection with the 2015 Credit Facility and an amendment to the 2015 Credit Facility (see Note 6). The warrants were exercisable at a price of $0.60 per share and $8.39 per share for the 2015 and 2017 issuances, respectively, and had a contractual term of ten years from issuance. The fair value of the warrants on the issuance date was recorded as a debt discount and as a preferred stock warrant liability. The Company remeasured the fair value of the liability for these preferred stock warrants at each reporting date and recorded any adjustments as other income (expense). The warrants outstanding at each reporting date were remeasured using the Black-Scholes option-pricing model, and the resulting change in fair value was recorded in other income (expense) in the Company’s condensed consolidated statements of operations and comprehensive loss. For the year ended December 31, 2018, the Company recorded other expense of $2.2 million to reflect the change in fair value of these preferred stock warrants. Upon the closing of the IPO in July 2018, the Company’s outstanding warrants to purchase preferred stock automatically became warrants to purchase an aggregate of 135,567 shares of common stock. In July 2018, the holders of such warrants completed a cashless exercise of the warrants, resulting in the Company’s issuance of 131,273 shares of common stock, whereby 4,294 shares of common stock were withheld by the Company to pay for the exercise price of the warrants.

8. Warrants to Purchase Convertible Preferred Stock

During 2015 and 2017, the Company issued warrants to purchase up to 133,333 shares of Series A Preferred Stock and 2,234 shares of Series B Preferred Stock, respectively, in connection with the 2015 Credit Facility and an amendment to the 2015 Credit Facility (see Note 6). The warrants were exercisable at a price of $0.60 per share and $8.39 per share for the 2015 and 2017 issuances, respectively, and had a contractual term of ten years from issuance. The fair value of the warrants on the issuance date was recorded as a debt discount and as a preferred stock warrant liability.

The Company remeasured the fair value of the liability for these preferred stock warrants at each reporting date and recorded any adjustments as other income (expense). The warrants outstanding at each reporting date were remeasured using the Black-Scholes option-pricing model, and the resulting change in fair value was recorded in other income (expense) in the Company’s condensed consolidated statements of operations and comprehensive loss. For the year ended December 31, 2018, the Company recorded other expense of $2.2 million to reflect the change in fair value of these preferred stock warrants.

Upon the closing of the IPO in July 2018, the Company’s outstanding warrants to purchase preferred stock automatically became warrants to purchase an aggregate of 135,567 shares of common stock. In July 2018, the holders of such warrants completed a cashless exercise of the warrants, resulting in the Company’s issuance of 131,273 shares of common stock, whereby 4,294 shares of common stock were withheld by the Company to pay for the exercise price of the warrants.