Stockholders' Equity	9 Months Ended
Sep. 30, 2021
Equity [Abstract]
Stockholders' Equity	9. Stockholders’ Equity In August 2021, the Company earned a $50,000 regulatory milestone from Vifor for the purchase of the Company’s common stock at a price of $15.23 per share. As of September 30, 2021, the Company recorded a stock subscription receivable of $44,969 in connection with the U.S. regulatory approval of KORSUVA injection, representing $15.23 per share, as well as license and milestone fees revenue of $5,031 representing the excess of the stock purchase price over the cost of the purchased shares at the closing price of the Company’s common stock on the date of the achievement of the milestone. In October 2021, after the expiration of the requisite waiting period under the Hart-Scott-Rodino Antitrust Improvement Act of 1976, or the HSR Act, the Company received the $50,000 payment and issued 3,282,391 shares of its common stock in connection with U.S. regulatory approval of KORSUVA injection on August 23, 2021 (see Notes 10, Collaboration and Licensing Agreements and 16, Subsequent Events). In August 2021, as a result of the achievement of certain performance targets, an aggregate of 44,002 performance-based restricted stock units of various executive officers vested and were settled in shares of the Company’s common stock (see Note 13, Stock-Based Compensation). In June 2021, as a result of the completion of the one-year vesting period, an aggregate of 36,000 restricted stock units of members of the Board of Directors vested and were settled in shares of the Company’s common stock (see Note 13, Stock-Based Compensation). In February and March 2021, as a result of the achievement of certain performance targets, an aggregate of 76,750 performance-based restricted stock units of various executive officers vested and were settled in shares of the Company’s common stock (see Note 13, Stock-Based Compensation). In February 2021, as a result of the completion of the first year of the three-year vesting period, an aggregate of 32,669 time-based restricted stock units of various executive officers vested and were settled in shares of the Company’s common stock (see Note 13, Stock-Based Compensation). In October 2020, the Company issued 2,939,552 shares of its common stock to Vifor in connection with the license agreement entered into with Vifor (see Note 10, Collaboration and Licensing Agreements). In June 2020, as a result of the completion of the one-year vesting period, an aggregate of 24,000 restricted stock units of members of the Board of Directors vested and were settled in shares of the Company’s common stock (see Note 13, Stock-Based Compensation). In April and June 2020, as a result of the achievement of certain performance targets, an aggregate of 95,834 restricted stock units of various executive officers vested and were settled in shares of the Company’s common stock (see Note 13, Stock-Based Compensation).

Stockholders' Equity

9 Months Ended

Sep. 30, 2021

9. Stockholders’ Equity

In August 2021, the Company earned a $50,000 regulatory milestone from Vifor for the purchase of the Company’s common stock at a price of $15.23 per share. As of September 30, 2021, the Company recorded a stock subscription receivable of $44,969 in connection with the U.S. regulatory approval of KORSUVA injection, representing $15.23 per share, as well as license and milestone fees revenue of $5,031 representing the excess of the stock purchase price over the cost of the purchased shares at the closing price of the Company’s common stock on the date of the achievement of the milestone. In October 2021, after the expiration of the requisite waiting period under the Hart-Scott-Rodino Antitrust Improvement Act of 1976, or the HSR Act, the Company received the $50,000 payment and issued 3,282,391 shares of its common stock in connection with U.S. regulatory approval of KORSUVA injection on August 23, 2021 (see Notes 10, Collaboration and Licensing Agreements and 16, Subsequent Events).

In August 2021, as a result of the achievement of certain performance targets, an aggregate of 44,002 performance-based restricted stock units of various executive officers vested and were settled in shares of the Company’s common stock (see Note 13, Stock-Based Compensation).

In June 2021, as a result of the completion of the one-year vesting period, an aggregate of 36,000 restricted stock units of members of the Board of Directors vested and were settled in shares of the Company’s common stock (see Note 13, Stock-Based Compensation).

In February and March 2021, as a result of the achievement of certain performance targets, an aggregate of 76,750 performance-based restricted stock units of various executive officers vested and were settled in shares of the Company’s common stock (see Note 13, Stock-Based Compensation).

In February 2021, as a result of the completion of the first year of the three-year vesting period, an aggregate of 32,669 time-based restricted stock units of various executive officers vested and were settled in shares of the Company’s common stock (see Note 13, Stock-Based Compensation).

In October 2020, the Company issued 2,939,552 shares of its common stock to Vifor in connection with the license agreement entered into with Vifor (see Note 10, Collaboration and Licensing Agreements).

In June 2020, as a result of the completion of the one-year vesting period, an aggregate of 24,000 restricted stock units of members of the Board of Directors vested and were settled in shares of the Company’s common stock (see Note 13, Stock-Based Compensation).

In April and June 2020, as a result of the achievement of certain performance targets, an aggregate of 95,834 restricted stock units of various executive officers vested and were settled in shares of the Company’s common stock (see Note 13, Stock-Based Compensation).