Long-term Debt - Additional Information (Detail)				6 Months Ended
		Jan. 08, 2020 USD ($) Tranche	Dec. 28, 2017 USD ($)	Jun. 30, 2021 USD ($)	Dec. 01, 2022 USD ($)	Dec. 31, 2020 USD ($)
Debt Instrument [Line Items]
Line of credit facility, advance amount				$ 20,000,000.0
Line of credit facility, interest rate		8.50%	8.05%
Borrowings outstanding				24,550,000
Discount on borrowings				$ 450,000
Minimum [Member]
Debt Instrument [Line Items]
Aggregate proceeds to be received from equity offering		$ 30,000,000.0
Hercules Capital Inc [Member]
Debt Instrument [Line Items]
Loan commitment fee, percentage		1.00%
Purchase of common stock		$ 1,000,000.0
Term Loan [Member]
Debt Instrument [Line Items]
Line of credit facility, maximum borrowing capacity			$ 50,000,000.0
Line of credit facility, interest rate				8.05%
Line of credit facility, interest rate description				As of June 30, 2021, the Company had borrowed $20.0 million under the Credit Facility, with an interest rate of 8.05% per annum and the remaining available amount had expired.
Line of credit facility, first principal and interest payment date				Jul. 01, 2021
Line of credit facility, maturity date				Dec. 01, 2022
Borrowings outstanding	[1]			$ 24,550,000		$ 24,401,000
Discount on borrowings				$ 450,000		$ 599,000
Term Loan [Member] | Minimum [Member]
Debt Instrument [Line Items]
Loan commitment charge		162,500
Term Loan [Member] | Forecast [Member]
Debt Instrument [Line Items]
Payment of end term charge					$ 1,300,000
Term Loan [Member] | Wall Street Journal Prime [Member]
Debt Instrument [Line Items]
Line of credit facility, interest rate				4.75%
Term Loan Restated [Member]
Debt Instrument [Line Items]
Line of credit facility, maximum borrowing capacity		$ 100,000,000.0
Line of credit facility, interest rate description				In addition, the Company may prepay advances under the Amended Loan Agreement, in whole or in part, at any time, subject to a prepayment charge that ranges from 1.0% to 2.0%, depending on the timing of the prepayment. The Amended Loan Agreement is secured by substantially all of the Company’s assets, excluding intellectual property.
Number of tranches | Tranche		3
Term Loan Restated [Member] | Minimum [Member]
Debt Instrument [Line Items]
Loan commitment charge		$ 520,000
Term Loan Restated [Member] | Hercules Capital Inc [Member] | Maximum [Member]
Debt Instrument [Line Items]
Amount of participation in equity financing		3,000,000.0
Term Loan Restated [Member] | Tranche One [Member]
Debt Instrument [Line Items]
Line of credit facility, advance amount				$ 5,000,000.0
Line of credit facility, interest rate				8.50%
Line of credit facility, interest rate description				Under the Restated Credit Facility, the Company borrowed $5.0 million from the first tranche with an interest rate of 8.50% per annum as of June 30, 2021.  Advances under the Restated Credit Facility bear an initial interest rate equal to the greater of either (i) 8.50% plus the Prime Rate minus 5.25%, and (ii) 8.50%, which may be reduced upon the Company achieving certain cumulative net avacopan revenue levels. For advances under the Restated Credit Facility, the Company will make interest only payments through September 1, 2022 and will then be obligated to repay the principal balance and interest on the advances in equal monthly installments through February 1, 2024. Upon satisfaction of certain conditions, the interest-only payment period and the principal balance repayment period may be extended.  In addition, the Company is obligated to pay an end of term charge of 7.15% of the aggregate amount of the advances under the Restated Credit Facility.
Line of credit facility, maturity date				Feb. 01, 2024
End of term charge advances, percentage				7.15%
Term Loan Restated [Member] | Wall Street Journal Prime [Member] | Tranche One [Member]
Debt Instrument [Line Items]
Line of credit facility, interest rate				5.25%
Through December 15, 2020 [Member] | Tranche One [Member]
Debt Instrument [Line Items]
Line of credit facility, maximum borrowing capacity		40,000,000.0
Through December 15, 2020 [Member] | Tranche One [Member] | Avacopan New Drug Application
Debt Instrument [Line Items]
Line of credit facility, capacity available for specific purpose other than for trade purchases		20,000,000.0
Through December 15, 2021 [Member] | Tranche Two [Member] | Avacopan New Drug Application
Debt Instrument [Line Items]
Restated credit facility, maximum borrowing capacity		30,000,000.0
Through December 15, 2022 [Member] | Tranche Three [Member]
Debt Instrument [Line Items]
Line of credit facility, maximum borrowing capacity		$ 30,000,000.0

[1] Carrying amounts of long-term debt were net of unamortized debt discounts of $450 and $599 as of June 30, 2021 and December 31, 2020, respectively