Summary of Significant Accounting Policies (Tables)

9 Months Ended

Sep. 30, 2020

Accounting Policies [Abstract]

Summary of Accounts Receivable

Total accounts receivable consists of the following (in thousands):

	September 30,		December 31,
	2020		2019
U.S. Food and Drug Administration	$	44	$	176
Vifor (International) Ltd., and/or its affiliates, or    collectively, Vifor		58		—
	$	102	$	176

Potentially Dilutive Securities Excluded from Calculation of Diluted Net Loss per Share Due to Anti-Dilutive Effect

For the three and nine months ended September 31, 2020 and 2019, the following potentially dilutive securities were excluded from the calculation of diluted net loss per share due to their anti-dilutive effect (in thousands):

	Three and Nine Months Ended September 30,
	2020		2019
Options to purchase common stock, including purchases    from contributions to ESPP		7,416		11,059
Restricted stock units		389		402
Restricted stock awards		14		41
Warrants to purchase common stock		150		150
		7,969		11,652