v2.4.0.6

Basis of Presentation (Details 6) (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Mar. 31, 2013	Mar. 31, 2012
Basis of Presentation [Line Items]
Share-based compensation expense total	$ 1,124	$ 709
Research and development expense [Member]
Basis of Presentation [Line Items]
Share-based compensation expense total	386	425
General and administrative expenses [Member]
Basis of Presentation [Line Items]
Share-based compensation expense total	$ 738	$ 284

X

- Details

Name:	lgnd_BasisOfPresentationLineItems
Namespace Prefix:	lgnd_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

X

- Definition

The amount of expense, net of income tax, recognized during the period arising from equity-based compensation arrangements (for example, shares of stock, unit, stock options or other equity instruments) with employees, directors and certain consultants qualifying for treatment as employees.

+ References

No definition available.

+ Details

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