CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS (Unaudited) - USD ($)		6 Months Ended
		Jun. 30, 2021	Jun. 30, 2020
OPERATING ACTIVITIES:
Net loss		$ (42,314,000)	$ (55,628,000)
Adjustments to reconcile net loss to net cash provided by operating activities:
Stock-based compensation expense		29,698,000	30,642,000
Depreciation		13,578,000	11,274,000
Amortization of tenant allowance		0	(258,000)
Amortization of purchased intangibles and finance leases		3,108,000	1,378,000
Amortization of debt issuance costs		1,228,000	600,000
Accretion of debt discount on convertible senior notes		16,374,000	4,777,000
Changes in fair value of contingent consideration		0	(263,000)
Allowance for credit losses		1,599,000	1,953,000
Gain on settlement of leases		(3,322,000)	0
Deferred income taxes		(1,408,000)	54,000
Changes in operating assets and liabilities:
Accounts receivable		(11,665,000)	10,051,000
Prepaid expenses and other current assets		(3,938,000)	(5,377,000)
Contract acquisition costs noncurrent		(3,557,000)	(4,348,000)
Other assets		597,000	(28,000)
Accounts payable		(6,548,000)	(3,026,000)
Accrued expenses and other current liabilities		20,527,000	14,235,000
Deferred revenue		20,126,000	5,979,000
Operating lease liabilities		(3,312,000)	270,000
Other liabilities		(157,000)	21,000
Net cash provided by operating activities		30,614,000	12,306,000
INVESTING ACTIVITIES:
Purchases of property and equipment, including capitalized software		(23,172,000)	(23,611,000)
Payments for intangible assets		(1,375,000)	(648,000)
Net cash used in investing activities		(24,547,000)	(24,259,000)
FINANCING ACTIVITIES:
Principal payments for financing leases		(1,728,000)	0
Proceeds from issuance of common stock in connection with the exercise of options and ESPP		9,001,000	9,123,000
Payments on conversion of convertible senior notes		(2,000)	0
Net cash provided by financing activities		7,271,000	9,123,000
Effect of foreign exchange rate changes on cash and cash equivalents		(1,882,000)	(516,000)
Net increase (decrease) in cash, cash equivalents, and restricted cash		11,456,000	(3,346,000)
Cash, cash equivalents, and restricted cash - beginning of year		654,152,000	176,523,000
Cash, cash equivalents, and restricted cash - end of year		665,608,000	173,177,000
Cash, Cash Equivalents, Restricted Cash and Restricted Cash Equivalents [Abstract]
Cash and cash equivalents		664,334,000	173,177,000
Restricted cash in prepaid expenses and other current assets		1,274,000	0
Total cash, cash equivalents, and restricted cash		665,608,000	173,177,000
Supplemental disclosure of other cash flow information:
Cash paid for income taxes		686,000	3,124,000
Cash paid for interest		1,041,000	863,000
Supplemental disclosure of non-cash investing and financing activities:
Purchase of property and equipment recorded in accounts payable		640,000	$ 1,198,000
Issuance of 11,508 shares of common stock as earnout payment in connection with AdvantageTec Inc. (shares)			11,508
Issuance of 11,508 shares of common stock as earn-out payment in connection with AdvantageTec Inc.		0	$ 294,000
Issuance of shares of common stock to settle cash awards		33,503,000	24,656,000
Right of use assets obtained in exchange for operating lease liabilities	[1]	$ 0	$ (1,050,000)

[1] Includes leases that commenced during the year ended December 31, 2020, as well as balances related to leases in existence as of the date of the adoption of Topic 842.