Condensed Consolidated Statements of Stockholders' Equity - USD ($) $ in Thousands	Total	Common Stock	Additional Paid-In Capital	Accumulated Other Comprehensive Income (Loss)	Accumulated Deficit
Balance at beginning of period (in shares) at Jan. 31, 2019		268,818,627,000
Stockholders' equity, beginning of period at Jan. 31, 2019	$ 1,562,069	$ 13	$ 2,711,340	$ (42)	$ (1,149,242)
Shares issued under employee stock plans (in shares)		841,981,000
Shares issued under employee stock plans	3,003	$ 1	3,002
Vested restricted stock units converted into shares (in shares)		5,191,871,000
Vested restricted stock units converted into shares	0
Stock-based compensation expense	48,871		48,871
Shares withheld related to net settlement of restricted stock units (in shares)		(667,983,000)
Shares withheld related to net settlement of restricted stock units	(7,805)		(7,805)
Unrealized gain on investments	350			350
Foreign currency translation adjustment	(8)			(8)
Net loss	(103,130)				(103,130)
Balance at end of period (in shares) at Apr. 30, 2019		274,184,496,000
Stockholders' equity, end of period at Apr. 30, 2019	1,503,350	$ 14	2,755,408	300	(1,252,372)
Balance at beginning of period (in shares) at Jan. 31, 2020		295,168,000
Stockholders' equity, beginning of period at Jan. 31, 2020	1,438,369	$ 15	2,923,905	273	(1,485,824)
Shares issued under employee stock plans (in shares)		154,000
Shares issued under employee stock plans	443		443
Vested restricted stock units converted into shares (in shares)		5,852,000
Vested restricted stock units converted into shares	$ 0
Repurchases of common stock (in shares)	(3,900,000)	(3,945,000)
Repurchases of common stock	$ (25,974)		(25,974)
Stock-based compensation expense	53,438		53,438
Shares withheld related to net settlement of restricted stock units (in shares)		(1,880,000)
Shares withheld related to net settlement of restricted stock units	(14,017)		(14,017)
Unrealized gain on investments	852			852
Foreign currency translation adjustment	(836)			(836)
Net loss	(58,014)				(58,014)
Balance at end of period (in shares) at Apr. 30, 2020		295,349,000
Stockholders' equity, end of period at Apr. 30, 2020	$ 1,393,463	$ 15	$ 2,937,795	$ 289	$ (1,544,636)