v2.4.1.9

Summary of Significant Accounting Policies Compensation Programs (Details)	12 Months Ended
	Dec. 31, 2014
Minimum [Member]
Forfeiture Rate [Line Items]
Forfeiture Rate	0.00%idcc_Sharebasedcompensationarrangementbysharebasedpaymentawardfairvalueassumptionsforfeiturerateptions / us-gaap_RangeAxis = us-gaap_MinimumMember
Maximum [Member]
Forfeiture Rate [Line Items]
Forfeiture Rate	25.00%idcc_Sharebasedcompensationarrangementbysharebasedpaymentawardfairvalueassumptionsforfeiturerateptions / us-gaap_RangeAxis = us-gaap_MaximumMember

X

- Details

Name:	idcc_ForfeitureRateLineItems
Namespace Prefix:	idcc_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

X

- Definition

Represents the rate at which stock options are expected to be forfeited by employees subsequent to their vest dates.

+ References

No definition available.

+ Details

Name:	idcc_Sharebasedcompensationarrangementbysharebasedpaymentawardfairvalueassumptionsforfeiturerateptions
Namespace Prefix:	idcc_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

X

- Details

Name:	us-gaap_RangeAxis=us-gaap_MaximumMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	us-gaap_RangeAxis=us-gaap_MinimumMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type: