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
	Mar. 31, 2021	Mar. 31, 2020
Numerator:
Net income (loss)	$ (10,692)	$ 6,307
Weighted average shares used to compute per share amount:
Basic (in shares)	50,717	48,615
Diluted (in shares)	50,717	50,617
Basic net income (loss) per share (in dollars per share)	$ (0.21)	$ 0.13
Diluted net income (loss) per share (in dollars per share)	$ (0.21)	$ 0.12