Stockholders' Equity (Tables)

6 Months Ended

Jun. 30, 2020

Equity [Abstract]

Summary of Reserved Shares of Common Stock for Future Issuance

The Company has reserved for future issuance the following number of shares of common stock:

	June 30, 2020	December 31, 2019
Common stock options and RSUs outstanding (1)	16,032,074	12,195,031
Shares available for issuance under Akebia equity    plans (2)	2,784,253	2,983,256
Warrant to purchase common stock	509,611	509,611
Shares available for issuance under the ESPP (3)	5,600,968	5,715,992
Total	24,926,906	21,403,890

(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, 2020, January 1, 2019 and January 1, 2018, the shares reserved for future grants under the 2014 Plan increased by 4,031,376, 3,801,198 and 1,575,329 shares, respectively, pursuant to the 2014 Plan Evergreen Provision. On December 12, 2018, the shares reserved for future grants under the 2014 Plan increased by 2,323,213 shares as a result of the Company’s addition of the Assumed Shares to the 2014 Plan. On January 30, 2019, the Company’s Board of Directors approved 3,150,000 shares for issuance as option awards in fiscal year 2019 under the Inducement Award Program.

(3)On June 6, 2019, the shares reserved for future issuance under the ESPP increased by 5,200,000 shares upon shareholder approval of the Amended and Restated 2014 Employee Stock Purchase Plan. On February 28, 2018 and February 28, 2017, the shares reserved for future issuance under the 2014 ESPP remained unchanged. There were no increases in the shares reserved for future issuance pursuant to the evergreen provision under the ESPP in 2017 and 2018 as the maximum aggregate number of shares available for purchase under the 2014 ESPP had reached its cap of 739,611 on February 28, 2016.

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:

	Three Months Ended				Six Months Ended
	June 30, 2020		June 30, 2019		June 30, 2020		June 30, 2019
	(in thousands)				(in thousands)
Research and development	$	1,716	$	684	$	3,258	$	1,562
Selling, general and administrative	5,148		1,600		8,522		2,816
Total	$	6,864	$	2,284	$	11,780	$	4,378

Schedule of Compensation Expense by Type of Award

Compensation expense by type of award:

	Three Months Ended				Six Months Ended
	June 30, 2020		June 30, 2019		June 30, 2020		June 30, 2019
	(in thousands)				(in thousands)
Stock options	$	2,366	$	1,073	$	3,983	$	2,185
Restricted stock units	4,344		1,168		7,486		2,102
Employee stock purchase plan	154		43		311		91
Total	$	6,864	$	2,284	$	11,780	$	4,378