Convertible Note Hedge

No definition available.

Name:	idcc_ConvertibleNoteHedge
Namespace Prefix:	idcc_
Data Type:	xbrli:sharesItemType
Balance Type:	na
Period Type:	instant

- Definition

Unamortized Debt Discount and Issuance Costs

+ References

No definition available.

+ Details

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Balance Type:	credit
Period Type:	instant

- Definition

Unwind Transactions, Shares

+ References

No definition available.

+ Details

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- Definition

Exercise price per share or per unit of warrants or rights outstanding.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 235
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.4-08.(i)(4))
-URI http://asc.fasb.org/extlink&oid=26873400&loc=d3e23780-122690

+ Details

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Data Type:	num:perShareItemType
Balance Type:	na
Period Type:	instant

- Definition

Number of securities into which the class of warrant or right may be converted. For example, but not limited to, 500,000 warrants may be converted into 1,000,000 shares.

+ References

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-Topic 235
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-Section S99
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-URI http://asc.fasb.org/extlink&oid=26873400&loc=d3e23780-122690

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Period Type:	instant

- Definition

The value of the financial instrument(s) that the original debt is being converted into in a noncash (or part noncash) transaction. "Part noncash" refers to that portion of the transaction not resulting in cash receipts or cash payments in the period.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
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-Section 50
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+ Details

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Balance Type:	credit
Period Type:	duration

- Definition

The price per share of the conversion feature embedded in the debt instrument.

+ References

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-Topic 470
-SubTopic 20
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-URI http://asc.fasb.org/extlink&oid=109500613&loc=SL6031898-161870

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Data Type:	num:perShareItemType
Balance Type:	na
Period Type:	instant

- Definition

Ratio applied to the conversion of debt instrument into equity with equity shares divided by debt principal amount.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
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+ Details

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Balance Type:	na
Period Type:	duration

- Definition

Face (par) amount of debt instrument at time of issuance.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 835
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+ Details

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Balance Type:	credit
Period Type:	instant

- Definition

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

+ References

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-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
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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.

+ Details

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- Definition

The cash inflow from additional borrowings, net of cash paid to third parties in connection with debt origination.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
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+ Details

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

The cash outflow for debt initially having maturity due after one year or beyond the normal operating cycle, if longer.

+ References

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- Details

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- Details

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- Details

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Period Type:

Long-Term Debt - 2024 and 2020 Senior Convertible Notes, and Related Note Hedge and Warrant Transactions (Details) $ / shares in Units, shares in Millions			6 Months Ended
	Jun. 03, 2019 USD ($) $ / shares	May 29, 2019 USD ($)	Jun. 30, 2020 USD ($) $ / shares shares	Jun. 30, 2019 USD ($)	Mar. 01, 2020 USD ($)	Dec. 31, 2019 USD ($)	May 31, 2019 $ / shares shares	Mar. 11, 2015 USD ($)	Mar. 09, 2015 shares
Debt Instrument [Line Items]
Initial strike price (in USD per share) \| $ / shares							$ 109.43
Payments on long-term debt		$ 221,100,000	$ 94,909,000	$ 221,091,000
Unwind transactions (in shares) \| shares			1.3
Convertible Notes 2020
Debt Instrument [Line Items]
Unamortized debt discount and issuance costs					$ 94,900,000
Convertible Debt
Debt Instrument [Line Items]
Aggregate principal amount			$ 400,000,000			$ 494,909,000
Convertible Debt \| Convertible Notes 2024
Debt Instrument [Line Items]
Aggregate principal amount	$ 400,000,000.0		400,000,000			400,000,000
Debt instrument interest rate, stated percentage	2.00%
Transaction fees and offering expenses	$ 391,600,000
Initial conversion rate	12.3018
Debt conversion converted instrument amount	$ 1,000		$ 1,000
Initial conversion price (in USD per share) \| $ / shares	$ 81.29
Convertible note hedge (in shares) \| shares							4.9
Anti-dilution adjustments of common stock (in shares) \| shares							4.9
Convertible Debt \| Convertible Notes 2020
Debt Instrument [Line Items]
Aggregate principal amount						$ 94,909,000		$ 316,000,000.0
Debt instrument interest rate, stated percentage								1.50%
Convertible note hedge (in shares) \| shares									4.4
Anti-dilution adjustments of common stock (in shares) \| shares									4.4
Initial strike price (in USD per share) \| $ / shares			$ 85.81