Summary of Significant Accounting Policies - Additional Information (Details)		1 Months Ended		12 Months Ended
	Sep. 25, 2018 USD ($)	Jan. 31, 2020 USD ($)	Jan. 31, 2017 USD ($)	Dec. 31, 2019 USD ($) Instrument	Dec. 31, 2018 USD ($) Instrument	Dec. 31, 2017 USD ($) Instrument	Jan. 01, 2019 USD ($)
Summary Of Significant Accounting Policies [Line Items]
Deferred revenue, revenue recognized				$ 101,100,000	$ 83,300,000	$ 76,400,000
Deferred commissions, amortization period				4 years
Amortization of deferred commissions				$ 2,700,000	1,600,000	1,000,000.0
Impairment loss related to deferred commissions				$ 0	0	0
Share-based compensation, fair value assumptions, expected dividend rate				0.00%
Cumulative amount of unrecognized stock-based compensation expense recognized	$ 89,900,000			$ 60,245,000	131,770,000	34,986,000
Remaining unamortized stock-based compensation				$ 6,200,000
Remaining weighted-average requisite service periods				1 year 1 month 6 days
Impairment of long-lived assets				$ 0		0
Impairment of property and equipment				0	2,821,000	0
Impairment of goodwill				0	0	0
Private company investment			$ 5,000,000.0	3,600,000	3,600,000
Impairments on private company investment				0	0	0
Observable price changes for private company investment				$ 0	$ 0	$ 0
Derivative financial instruments outstanding | Instrument				0	0	0
Deferred rent balance					$ 7,500,000
Liability for sabbatical leave, accrued balance				$ 3,800,000	4,400,000
Advertising and promotion costs				30,300,000	25,700,000	$ 19,400,000
Cash consideration from sale of private company investment			$ 11,700,000
Gain on sale of private company investment				$ 1,001,000	999,000	$ 6,750,000
Sale of private company investment, period of contingent consideration to be received				3 years
Earn-out payment received				$ 1,000,000.0	1,000,000.0
Recognition of ROU assets				63,904,000	0
Operating lease liabilities				91,049,000
Subsequent Event
Summary Of Significant Accounting Policies [Line Items]
Earn-out payment received		$ 1,000,000.0
Accrued Expenses And Other Current Liabilities
Summary Of Significant Accounting Policies [Line Items]
Deferred rent balance					300,000
Other Non-Current Liabilities
Summary Of Significant Accounting Policies [Line Items]
Deferred rent balance					7,200,000
Liability for sabbatical leave, accrued balance				2,100,000	2,100,000
Accrued Compensation
Summary Of Significant Accounting Policies [Line Items]
Liability for sabbatical leave, accrued balance				$ 1,700,000	$ 2,300,000
ASC 842
Summary Of Significant Accounting Policies [Line Items]
Recognition of ROU assets							$ 63,100,000
Operating lease liabilities							$ 92,800,000
ASC 842 | Minimum
Summary Of Significant Accounting Policies [Line Items]
Operating lease terms				1 year
ASC 842 | Maximum
Summary Of Significant Accounting Policies [Line Items]
Operating lease terms				12 years
Capitalized Internal-Use Software
Summary Of Significant Accounting Policies [Line Items]
Intangible assets estimated useful life				3 years
Customer Concentration Risk | Sales Revenue, Net
Summary Of Significant Accounting Policies [Line Items]
Concentration of credit risk, customer				No single customer accounted for more than 10% of revenue	No single customer accounted for more than 10% of revenue	No single customer accounted for more than 10% of revenue
Customer Concentration Risk | Accounts Receivable
Summary Of Significant Accounting Policies [Line Items]
Concentration of credit risk, customer				No customers accounted for more than 10% of accounts receivable, net	No customers accounted for more than 10% of accounts receivable, net
Equity Incentive Plans | Time-Based Awards | New Hires
Summary Of Significant Accounting Policies [Line Items]
Stock-based compensation, requisite service period				4 years
Equity Incentive Plans | Time-Based Awards | Existing Employees
Summary Of Significant Accounting Policies [Line Items]
Stock-based compensation, requisite service period				3 years