Net Loss Per Share - Computation of Net Loss Per Share Attributable to Common Stockholders, Basic and Diluted (Detail) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	12 Months Ended
	Mar. 31, 2019	Mar. 31, 2018	Mar. 31, 2017
Numerator:
Net loss attributable to New Relic	$ (40,893)	$ (45,320)	$ (61,077)
Denominator:
Weighted-average shares used to compute net loss per share, basic and diluted (in shares)	56,884	54,814	51,715
Net loss per share, basic and diluted (in usd per share)	$ (0.72)	$ (0.83)	$ (1.18)