Derivative liabilities and changes in fair value.

No definition available.

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- Definition

Amount of write-down of assets recognized in the income statement. Includes, but is not limited to, losses from tangible assets, intangible assets and goodwill.

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- Definition

Amount of increase (decrease) in the value of a contingent consideration liability, including, but not limited to, differences arising upon settlement.

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Publisher FASB
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-SubTopic 10
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- Definition

Aggregate number of common shares reserved for future issuance.

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- Definition

Fair value portion of borrowing which can be exchanged for a specified number of another security at the option of the issuer or the holder, for example, but not limited to, the entity's common stock.

+ References

No definition available.

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- Definition

Carrying amount of long-term convertible debt as of the balance sheet date, net of the amount due in the next twelve months or greater than the normal operating cycle, if longer. The debt is convertible into another form of financial instrument, typically the entity's common stock.

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- Definition

Contractual interest rate for funds borrowed, under the debt agreement.

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- Definition

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

+ References

No definition available.

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Fair Value Measurements - Additional Information (Details) - USD ($)	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018	May 27, 2020	Nov. 30, 2017
Fair Value Liabilities Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]
Asset impairment charges	$ 0
Common stock reserved for future issuance	4,800,000
Change in fair value of contingent consideration obligation	$ 3,665,000	$ (550,000)	$ (250,000)
Carrying value of convertible senior notes	$ 441,514,000	$ 430,282,000
0.125% Convertible Senior Notes Due 2024
Fair Value Liabilities Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]
Debt instrument, interest rate	0.125%	0.125%
Fair value of convertible senior notes	$ 663,600,000	$ 450,400,000
Carrying value of convertible senior notes	$ 369,000,000.0	$ 351,100,000
1.50% Convertible Senior Notes Due 2022
Fair Value Liabilities Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]
Debt instrument, interest rate	1.50%	1.50%			1.50%
Fair value of convertible senior notes	$ 265,500,000	$ 215,800,000
Carrying value of convertible senior notes	72,500,000	79,200,000
Techwan SA
Fair Value Liabilities Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]
Common stock reserved for future issuance				6,779
Change in fair value of contingent consideration obligation	(2,000,000.0)
Techwan SA \| Other Expense, Net
Fair Value Liabilities Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]
Derivative liabilities and changes in fair value	100,000
One2Many Group B.V.
Fair Value Liabilities Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]
Change in fair value of contingent consideration obligation	8,100,000
SnapComms Limited
Fair Value Liabilities Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]
Change in fair value of contingent consideration obligation	(2,000,000.0)
Fair Value Measurements, Nonrecurring
Fair Value Liabilities Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]
Asset impairment charges	$ 0	$ 0	$ 0