Net Loss per Share (Tables)

12 Months Ended

Dec. 31, 2021

Earnings Per Share [Abstract]

Anti-Dilutive Securities Excluded from Calculation of Diluted Net Loss per Share

The shares in the table below were excluded from the calculation of diluted net loss per share, prior to the use of the treasury stock method, due to their anti-dilutive effect:

	Year ended December 31,
	2021	2020	2019
Warrants	509,611	509,611	509,611
Outstanding stock options	11,398,215	9,386,517	7,670,899
Unvested restricted stock units	4,667,003	4,722,311	4,524,132
Total	16,574,829	14,618,439	12,704,642