Condensed Consolidated Statements of Stockholders' Equity - USD ($) shares in Thousands, $ in Thousands	Total	Common Stock	Additional Paid-In Capital	Treasury Stock	Accumulated Other Comprehensive Income (Loss)	Accumulated Deficit
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Cumulative effect adjustment for ASU 2014-09 adoption	$ 40,813					$ 40,813
Beginning balance (in shares) at Mar. 31, 2018		56,213		260
Beginning balance at Mar. 31, 2018	215,104	$ 56	$ 521,119	$ (263)	$ (324)	(305,484)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Purchase of capped calls	(63,200)
Ending balance (in shares) at Sep. 30, 2018		57,199		260
Ending balance at Sep. 30, 2018	317,847	$ 57	597,248	$ (263)	(573)	(278,622)
Beginning balance (in shares) at Mar. 31, 2018		56,213		260
Beginning balance at Mar. 31, 2018	215,104	$ 56	521,119	$ (263)	(324)	(305,484)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Issuance of common stock upon exercise of stock options (in shares)		552
Issuance of common stock upon exercise of stock options	11,536	$ 1	11,535
Issuance of common stock for vested restricted stock units (in shares)		688
Issuance of common stock related to employee stock purchase plan (in shares)		83
Issuance of common stock related to employee stock purchase plan	4,887		4,887
Stock-based compensation expense	40,179		40,179
Other comprehensive income (loss), net	363				363
Net loss attributable to New Relic	(24,054)					(24,054)
Equity component of convertible senior notes, net of issuance costs	100,136		100,136
Purchase of capped calls	(63,182)		(63,182)
Ending balance (in shares) at Dec. 31, 2018		57,536		260
Ending balance at Dec. 31, 2018	325,782	$ 57	614,674	$ (263)	39	(288,725)
Beginning balance (in shares) at Sep. 30, 2018		57,199		260
Beginning balance at Sep. 30, 2018	317,847	$ 57	597,248	$ (263)	(573)	(278,622)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Issuance of common stock upon exercise of stock options (in shares)		97
Issuance of common stock upon exercise of stock options	2,519		2,519
Issuance of common stock for vested restricted stock units (in shares)		240
Stock-based compensation expense	14,907		14,907
Other comprehensive income (loss), net	612				612
Net loss attributable to New Relic	(10,103)					(10,103)
Ending balance (in shares) at Dec. 31, 2018		57,536		260
Ending balance at Dec. 31, 2018	325,782	$ 57	614,674	$ (263)	39	(288,725)
Beginning balance (in shares) at Mar. 31, 2019		58,366		260
Beginning balance at Mar. 31, 2019	$ 349,630	$ 58	654,759	$ (263)	645	(305,569)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Issuance of common stock upon exercise of stock options (in shares)	267	267
Issuance of common stock upon exercise of stock options	$ 6,773		6,773
Issuance of common stock for vested restricted stock units (in shares)		650
Issuance of common stock for vested restricted stock units		$ 1	(1)
Issuance of common stock related to employee stock purchase plan (in shares)		117
Issuance of common stock related to employee stock purchase plan	5,933		5,933
Stock-based compensation expense	70,899		70,899
Other comprehensive income (loss), net	1,262				1,262
Net loss attributable to New Relic	(60,978)					(60,978)
Ending balance (in shares) at Dec. 31, 2019		59,400		260
Ending balance at Dec. 31, 2019	373,519	$ 59	738,363	$ (263)	1,907	(366,547)
Beginning balance (in shares) at Sep. 30, 2019		59,036		260
Beginning balance at Sep. 30, 2019	371,160	$ 59	708,761	$ (263)	1,955	(339,352)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Issuance of common stock upon exercise of stock options (in shares)		146
Issuance of common stock upon exercise of stock options	3,719		3,719
Issuance of common stock for vested restricted stock units (in shares)		218
Stock-based compensation expense	25,883		25,883
Other comprehensive income (loss), net	(48)				(48)
Net loss attributable to New Relic	(27,195)					(27,195)
Ending balance (in shares) at Dec. 31, 2019		59,400		260
Ending balance at Dec. 31, 2019	$ 373,519	$ 59	$ 738,363	$ (263)	$ 1,907	$ (366,547)