v3.23.2
Stockholders' Equity (Tables)
 12 Months Ended
Dec. 31, 2022
Equity [Abstract]  
Reserved Shares of Common Stock for Future Issuance The Company has reserved for future issuance the following number of shares of common stock:
 December 31, 2022December 31, 2021
Common stock options, RSUs and PSUs outstanding (1)
17,407,227 16,065,218 
Shares available for issuance under Akebia equity plans (2)
5,498,984 4,675,734 
Warrant to purchase common stock— 509,611 
Shares available for issuance under the ESPP4,837,995 5,173,141 
Total27,744,206 26,423,704 
 
(1)Includes awards granted under the 2014 Plan and the Inducement Award Program and awards issued in connection with the Merger.
(2)On January 1, 2023, January 1, 2022 and January 1, 2021, the shares reserved for future grants under the 2014 Plan increased by 6,046,288, 5,807,270 and 4,880,775 shares, respectively, pursuant to the 2014 Plan Evergreen Provision.
Assumptions Used in Black-Scholes Option Pricing Model
The assumptions used in the Black-Scholes pricing model to estimate the grant date fair value of options granted under the 2014 Plan are as follows:
 Year ended December 31,
 202220212020
Risk-free interest rate1.69%-4.17%0.66%-1.37%0.32%-1.38%
Dividend yield—%—%—%
Volatility79.77%-91.57%77.81%-81.79%69.56%-75.91%
Expected term (years)5.51-6.255.51-6.255.51-6.25
Stock Option Activity
The following table summarizes the Company’s stock option activity, excluding performance-based options, for the year ended December 31, 2022:
 SharesWeighted-Average
Exercise Price		Weighted-Average
Contractual Life
(in years)		Aggregate
Intrinsic Value
Outstanding, December 31, 202111,398,215 $7.60 $267,830 
Granted3,809,200 $1.81 
Exercised(142,440)$0.47 $44,905 
Forfeited(3,331,840)$6.43 $3,813 
Expired/cancelled(407,045)$9.52 
Outstanding, December 31, 202211,326,090 $6.01 7.26$112,709 
Options exercisable, December 31, 20226,239,437 $8.37 6.08$1,904 
Vested and expected to vest, December 31, 202211,326,090 $6.01 
Performance-based Option Activity
The following table summarizes the Company’s performance-based option activity for the year ended December 31, 2022:
 SharesWeighted-Average
Exercise Price		Weighted-Average
Contractual Life
(in years)		Aggregate
Intrinsic Value
Outstanding, December 31, 202199,558 $2.74 $— 
Granted400,000 $0.41 $1,120 
Exercised— $— $— 
Forfeited/cancelled(99,558)$2.74 
Outstanding, December 31, 2022400,000 $0.41 9.4$66,800 
Restricted Stock and Performance-Based Restricted Stock Units Activity The following table summarizes the Company’s RSU and PSU activity for the year ended December 31, 2022:
 
 SharesWeighted-
Average Grant
Date Fair Value
Unvested balance, December 31, 20214,554,343 $5.17 
Granted5,715,808 $1.30 
Vested(2,252,565)$5.01 
Forfeited(2,349,551)$3.33 
Unvested balance, December 31, 20225,668,035 $2.09 
Stock-Based Compensation Expense Related to Share-Based Awards
The Company has classified its stock-based compensation expense related to share-based awards as follows (in thousands):
 Years ended December 31,
 202220212020
Research and development$3,683 $5,816 $6,113 
Selling, general and administrative10,969 16,919 18,347 
Total$14,652 $22,735 $24,460 
Compensation Expense by Type of Award
Compensation expense by type of award (in thousands):
 Years ended December 31,
 202220212020
Stock options$6,839 $8,958 $8,517 
Restricted stock units7,566 12,927 14,639 
Performance RSUs100 294 464 
Employee stock purchase plan147 556 840 
Total$14,652 $22,735 $24,460