Summary of Significant Accounting Policies - Summary of Calculation of Basic and Diluted Net Loss Per Share (Detail) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended
	Mar. 31, 2020	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019
Accounting Policies [Abstract]
Net loss	$ (2,244)	$ 9,553	$ 7,816	$ (26,228)	$ (3,488)
Net loss per share:
Basic net loss per share (in usd per share)	$ (0.02)				$ (0.02)
Diluted net loss per share (in usd per share)	$ (0.02)				$ (0.02)
Weighted-average common shares used in computing net loss per share:
Basic (in shares)	146,027,241				143,512,293
Diluted (in shares)	146,027,241				143,512,293