Common Stock Subject to Conditional Redemption - Pfizer Settlement Agreement	9 Months Ended
Sep. 30, 2013
Common Stock Subject to Conditional Redemption - Pfizer Settlement Agreement [Abstract]
Common Stock Subject to Conditional Redemption - Pfizer Settlement Agreement	Common Stock Subject to Conditional Redemption - Pfizer Settlement Agreement In April 1996, the Company and Pfizer entered into a settlement agreement with respect to a lawsuit filed in December 1994 by the Company against Pfizer. In connection with a collaborative research agreement the Company entered into with Pfizer in 1991, Pfizer purchased shares of the Company’s common stock. Under the terms of the settlement agreement, at the option of either the Company or Pfizer, milestone and royalty payments owed to the Company can be satisfied by Pfizer by transferring to the Company shares of the Company’s common stock at an exchange ratio of $74.25 per share, for revenue related to lasofoxifene and drolofoxifene. The remaining common stock issued and outstanding to Pfizer following the settlement was reclassified as common stock subject to conditional redemption (between liabilities and equity) since Pfizer has the option to settle milestone and royalties payments owed to the Company with the Company’s shares, and such option is not within the Company’s control. The remaining shares of the Company’s common stock that could be redeemed totaled 112,371 and are reflected at the exchange ratio price of $74.25. Pfizer notified Ligand that the development of the two compounds covered under the 1996 settlement agreement were terminated and thus the Company reclassified the shares and the current carrying amount of $8.3 million to permanent equity in the first quarter of 2012.

Common Stock Subject to Conditional Redemption - Pfizer Settlement Agreement

In April 1996, the Company and Pfizer entered into a settlement agreement with respect to a lawsuit filed in December 1994 by the Company against Pfizer. In connection with a collaborative research agreement the Company entered into with Pfizer in 1991, Pfizer purchased shares of the Company’s common stock. Under the terms of the settlement agreement, at the option of either the Company or Pfizer, milestone and royalty payments owed to the Company can be satisfied by Pfizer by transferring to the Company shares of the Company’s common stock at an exchange ratio of $74.25 per share, for revenue related to lasofoxifene and drolofoxifene. The remaining common stock issued and outstanding to Pfizer following the settlement was reclassified as common stock subject to conditional redemption (between liabilities and equity) since Pfizer has the option to settle milestone and royalties payments owed to the Company with the Company’s shares, and such option is not within the Company’s control. The remaining shares of the Company’s common stock that could be redeemed totaled 112,371 and are reflected at the exchange ratio price of $74.25. Pfizer notified Ligand that the development of the two compounds covered under the 1996 settlement agreement were terminated and thus the Company reclassified the shares and the current carrying amount of $8.3 million to permanent equity in the first quarter of 2012.