CONSOLIDATED STATEMENTS OF STOCKHOLDERS EQUITY - USD ($) $ in Thousands	Total		Class A and Class B Common Stock	Class A and Class B Common Stock Non-employee	Additional Paid-in Capital	Treasury Stock	Accumulated Other Comprehensive (Loss) Income	Accumulated Deficit
Balance, Beginning at Jan. 31, 2016	$ 137,901		$ 12		$ 871,491	$ (1,177)	$ (84)	$ (732,341)
Balance, Beginning, Shares at Jan. 31, 2016			124,121,000
Issuance of common stock upon stock option exercises	11,087		$ 1		11,086
Issuance of common stock upon stock option exercises (in shares)			2,908,000
Issuance of common stock in connection with acquisitions	1,011				1,011
Issuance of common stock in connection with acquisitions (in shares)			71,000
Issuance of common stock in connection with prior year acquisitions (in shares)			8,000
Stock-based compensation related to stock awards	78,372				78,372
Vesting of restricted stock units and restricted stock awards, net of shares withheld for employee payroll taxes (in shares)			1,987,000
Employee payroll taxes withheld related to vesting of restricted stock units and restricted stock awards	(17,552)				(17,552)
Common stock issued to non-employees for services rendered (in shares)				8,000
Vesting of shares subject to repurchase	10				10
Common stock issued under employee stock purchase plan	15,726				15,726
Common stock issued under employee stock purchase plan (in shares)			1,508,000
Other comprehensive income (loss)	(36)	[1],[2]					(36)
Net loss	(151,787)	[1]						(151,787)
Balance, Ending at Jan. 31, 2017	74,732		$ 13		960,144	(1,177)	(120)	(884,128)
Balance, Ending, Shares at Jan. 31, 2017			130,611,000
Issuance of common stock upon stock option exercises	$ 14,558				14,558
Issuance of common stock upon stock option exercises (in shares)	2,098,726		2,099,000
Stock-based compensation related to stock awards	$ 97,485				97,485
Vesting of restricted stock units and restricted stock awards, net of shares withheld for employee payroll taxes (in shares)			3,008,000
Employee payroll taxes withheld related to vesting of restricted stock units and restricted stock awards	(34,776)				(34,776)
Common stock issued under employee stock purchase plan	17,521				17,521
Common stock issued under employee stock purchase plan (in shares)			1,599,000
Other comprehensive income (loss)	408	[1],[2]					408
Net loss	(154,960)	[1]						(154,960)
Balance, Ending at Jan. 31, 2018	14,968	[1]	$ 13		1,054,932	(1,177)	288	(1,039,088)
Balance, Ending, Shares at Jan. 31, 2018			137,317,000
Issuance of common stock upon stock option exercises	$ 16,326				16,326
Issuance of common stock upon stock option exercises (in shares)	1,980,070		1,980,000
Issuance of common stock in connection with acquisitions	$ 1,053				1,053
Issuance of common stock in connection with acquisitions (in shares)			40,000
Issuance of common stock in connection with charitable donations	243				243
Issuance of common stock in connection with charitable donations (in shares)			12,000
Stock-based compensation related to stock awards	115,852				115,852
Vesting of restricted stock units, net of shares withheld for employee payroll taxes	1		$ 1
Vesting of restricted stock units and restricted stock awards, net of shares withheld for employee payroll taxes (in shares)			3,345,000
Employee payroll taxes withheld related to vesting of restricted stock units and restricted stock awards	(43,824)				(43,824)
Cumulative effect of ASC adoption | Topic 606	39,802							39,802
Common stock issued under employee stock purchase plan	21,861				21,861
Common stock issued under employee stock purchase plan (in shares)			1,617,000
Other comprehensive income (loss)	(265)	[2],[3]					(265)
Net loss	(134,612)	[3]						(134,612)
Balance, Ending at Jan. 31, 2019	$ 31,405	[3]	$ 14		$ 1,166,443	$ (1,177)	$ 23	$ (1,133,898)
Balance, Ending, Shares at Jan. 31, 2019			144,311,000

[1] As reported under ASC Topic 605

[2] Tax effect was not material

[3] As reported under ASC Topic 606