Related Party Transactions	12 Months Ended
Dec. 31, 2021
Related Party Transactions [Abstract]
Related Party Transactions	12. Related Party Transactions Kenneth A. Clark, a director of the Company from November 2017 to October 2021, is a member of the law firm of Wilson Sonsini Goodrich and Rosati (“WSGR”), which also served as the outside corporate counsel to the Company until November 18, 2021. During the years ended December 31, 2021, 2020 and 2019, the Company incurred expenses reported in general and administrative expenses in the consolidated statement of operations for legal services rendered by WSGR totaling approximately $0.6 million, $0.8 million and $0.5 million, respectively. During the year ended December 31, 2021, the Company capitalized approximately $0.2 million for legal expenses incurred in connection with the Sales Agreement. During the year ended December 31, 2020, the Company capitalized approximately $0.4 million for legal expenses incurred in connection with the 2020 rights offering. In October 2021, Mr. Clark resigned from the Company’s Board of Directors, and in November 2021, the Board terminated the engagement of WSGR and appointed Baker & Hostetler LLP as the Company’s outside corporate counsel. In May 2020, the Company determined not to renew its director and officer liability insurance policies due to disproportionately high premiums quoted by insurance companies. Instead, Robert W. Duggan, majority stockholder and Board Chairman, and the Company entered into a letter agreement, dated May 12, 2020 (the “Letter Agreement”), pursuant to which Mr. Duggan agreed with the Company to personally provide indemnity coverage on substantially the same terms as the Company’s prior coverage program for a one-year period, and has deposited security for such obligations. On May 13, 2021, in accordance with terms of the Letter Agreement, the Company paid Mr. Duggan the amount of $2.5 million. The Company did not enter into a new Letter Agreement with Mr. Duggan for the subsequent policy period, and in May 2021 secured its director and officer liability insurance through third-party insurance carriers. In June 2020, the Company completed the Rights Offering (Note 6). Mr. Duggan participated in the Rights Offering and purchased an aggregate of 2,561,873 Units.On March 11, 2021, the Company and Mr. Duggan entered into a Loan Agreement in connection with Mr. Duggan lending the principal sum of $41.0 million to the Company (Note 13).On June 30, 2021, the Company and Mr. Duggan entered into a Securities Purchase Agreement (Note 6), pursuant to which the Company issued and sold to Mr. Duggan 3,048,780 shares of the Company’s common stock, par value $0.001 per share, in a Private Placement, at a price per share of $16.40, for an aggregate investment in the amount of $50.0 million. The shares were paid for through (i) the conversion of the $41 million aggregate principal amount under the Loan Agreement, together with all accrued and unpaid interest outstanding, owed to Mr. Duggan under the Loan Agreement by and between the Company and Mr. Duggan (Note 13), and (ii) additional cash in the amount of approximately $8.4 million. Upon the closing of this Private Placement and satisfaction of the outstanding debt, the Loan Agreement terminated, without any early termination fees or penalties being owed by the Company, and no additional amounts were owed to Mr. Duggan under the Loan Agreement.

Related Party Transactions

12 Months Ended

Dec. 31, 2021

12. Related Party Transactions Kenneth A. Clark, a director of the Company from November 2017 to October 2021, is a member of the law firm of Wilson Sonsini Goodrich and Rosati (“WSGR”), which also served as the outside corporate counsel to the Company until November 18, 2021. During the years ended December 31, 2021, 2020 and 2019, the Company incurred expenses reported in general and administrative expenses in the consolidated statement of operations for legal services rendered by WSGR totaling approximately $0.6 million, $0.8 million and $0.5 million, respectively. During the year ended December 31, 2021, the Company capitalized approximately $0.2 million for legal expenses incurred in connection with the Sales Agreement. During the year ended December 31, 2020, the Company capitalized approximately $0.4 million for legal expenses incurred in connection with the 2020 rights offering. In October 2021, Mr. Clark resigned from the Company’s Board of Directors, and in November 2021, the Board terminated the engagement of WSGR and appointed Baker & Hostetler LLP as the Company’s outside corporate counsel. In May 2020, the Company determined not to renew its director and officer liability insurance policies due to disproportionately high premiums quoted by insurance companies. Instead, Robert W. Duggan, majority stockholder and Board Chairman, and the Company entered into a letter agreement, dated May 12, 2020 (the “Letter Agreement”), pursuant to which Mr. Duggan agreed with the Company to personally provide indemnity coverage on substantially the same terms as the Company’s prior coverage program for a one-year period, and has deposited security for such obligations. On May 13, 2021, in accordance with terms of the Letter Agreement, the Company paid Mr. Duggan the amount of $2.5 million. The Company did not enter into a new Letter Agreement with Mr. Duggan for the subsequent policy period, and in May 2021 secured its director and officer liability insurance through third-party insurance carriers. In June 2020, the Company completed the Rights Offering (Note 6). Mr. Duggan participated in the Rights Offering and purchased an aggregate of 2,561,873 Units.On March 11, 2021, the Company and Mr. Duggan entered into a Loan Agreement in connection with Mr. Duggan lending the principal sum of $41.0 million to the Company (Note 13).On June 30, 2021, the Company and Mr. Duggan entered into a Securities Purchase Agreement (Note 6), pursuant to which the Company issued and sold to Mr. Duggan 3,048,780 shares of the Company’s common stock, par value $0.001 per share, in a Private Placement, at a price per share of $16.40, for an aggregate investment in the amount of $50.0 million. The shares were paid for through (i) the conversion of the $41 million aggregate principal amount under the Loan Agreement, together with all accrued and unpaid interest outstanding, owed to Mr. Duggan under the Loan Agreement by and between the Company and Mr. Duggan (Note 13), and (ii) additional cash in the amount of approximately $8.4 million. Upon the closing of this Private Placement and satisfaction of the outstanding debt, the Loan Agreement terminated, without any early termination fees or penalties being owed by the Company, and no additional amounts were owed to Mr. Duggan under the Loan Agreement.