Net income (loss) per share - Computation of Basic and Diluted Net Income (Loss) Per Share (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Numerator:
Net income (loss)	$ (1,860)	$ (4,903)	$ (29,984)	$ 7,129
Weighted average shares used to compute per share amount:
Basic (in shares)	52,427	49,936	51,599	49,212
Diluted (in shares)	52,427	49,936	51,599	51,411
Basic net income (loss) per share (in dollars per share)	$ (0.04)	$ (0.10)	$ (0.58)	$ 0.14
Diluted net income (loss) per share (in dollars per share)	$ (0.04)	$ (0.10)	$ (0.58)	$ 0.14