Related Party Transactions	9 Months Ended
Sep. 30, 2019
Related Party Transactions
Related Party Transactions	Note 12. Related Party Transactions Overview of Related Parties Julian C. Baker, a member of the Company’s Board until his resignation in September 2018, is a principal of Baker Bros. Advisors, LP. Additionally, Kelvin M. Neu, a member of Company’s Board until his resignation in June 2019, is an employee of Baker Bros. Advisors, LP. As of September 30, 2019, Baker Bros. Advisors, LP and certain of its affiliated funds (collectively, “Baker Brothers”) held sole voting power with respect to an aggregate of 4,606,786 shares of the Company’s common stock, representing approximately 16% of the Company's outstanding common stock. During the nine months ended September 30, 2019, Baker Brothers made an in-kind pro rata distribution of a total of 60,070 warrants to purchase shares of the Company’s common stock to Mr. Baker, Mr. Neu and other investors in Baker Brothers. During the nine months ended September 30, 2018, Baker Brothers exercised warrants to purchase 2,539,541 shares of the Company’s common stock at an exercise price of $3.76 per share for a total exercise price of approximately $9.5 million. As of September 30, 2019, Baker Brothers held pre-funded warrants to purchase up to 2,708,812 shares of the Company’s common stock at an exercise price of $0.08 per share. Board Fees Paid in Stock Pursuant to the Company’s director compensation program, in lieu of director board and committee fees incurred of $0.1 million during each of the nine months ended September 30, 2019 and 2018, the Company issued 40,158 and 7,067 shares of its common stock, respectively, to certain of its directors. Director board and committee fees are paid in arrears (including fees paid in stock) and the number of shares issued was calculated based on the market closing price of the Company’s common stock on the issuance date.

Note 12. Related Party Transactions

Overview of Related Parties

Julian C. Baker, a member of the Company’s Board until his resignation in September 2018, is a principal of Baker Bros. Advisors, LP. Additionally, Kelvin M. Neu, a member of Company’s Board until his resignation in June 2019, is an employee of Baker Bros. Advisors, LP. As of September 30, 2019, Baker Bros. Advisors, LP and certain of its affiliated funds (collectively, “Baker Brothers”) held sole voting power with respect to an aggregate of 4,606,786 shares of the Company’s common stock, representing approximately 16% of the Company's outstanding common stock.

During the nine months ended September 30, 2019, Baker Brothers made an in-kind pro rata distribution of a total of 60,070 warrants to purchase shares of the Company’s common stock to Mr. Baker, Mr. Neu and other investors in Baker Brothers. During the nine months ended September 30, 2018, Baker Brothers exercised warrants to purchase 2,539,541 shares of the Company’s common stock at an exercise price of $3.76 per share for a total exercise price of approximately $9.5 million.

As of September 30, 2019, Baker Brothers held pre-funded warrants to purchase up to 2,708,812 shares of the Company’s common stock at an exercise price of $0.08 per share.

Board Fees Paid in Stock

Pursuant to the Company’s director compensation program, in lieu of director board and committee fees incurred of $0.1 million during each of the nine months ended September 30, 2019 and 2018, the Company issued 40,158 and 7,067 shares of its common stock, respectively, to certain of its directors. Director board and committee fees are paid in arrears (including fees paid in stock) and the number of shares issued was calculated based on the market closing price of the Company’s common stock on the issuance date.