Fair Value Measurements - Carrying Values of Our Cash and Cash Equivalents, Marketable Securities, Other Securities and Common Stock Warrants, Carried at Fair Value (Detail) (USD $) In Thousands, unless otherwise specified	Jun. 30, 2013	Dec. 31, 2012
Assets:
Cash and equivalents	$ 121,103	$ 139,698
Cash and equivalents, and marketable securities and investments	124,415
Deferred compensation investments, including life insurance cash surrender value	4,311
Other securities	3,449
Total Assets	132,175
Liabilities:
Deferred executive compensation liability	3,206
Deferred development costs	18,651
Melphalan license contingent consideration	4,700
Contingent value right
Total Liabilities	26,557
Bank CDs [Member]
Assets:
Marketable securities, fair value	252
Money market currency funds [Member]
Assets:
Marketable securities, fair value	3,060
Level 1 [Member]
Assets:
Cash and equivalents	121,103
Cash and equivalents, and marketable securities and investments	121,103
Deferred compensation investments, including life insurance cash surrender value
Other securities	3,449
Total Assets	124,552
Liabilities:
Deferred executive compensation liability
Deferred development costs
Melphalan license contingent consideration
Contingent value right
Total Liabilities
Level 1 [Member] | Bank CDs [Member]
Assets:
Marketable securities, fair value
Level 1 [Member] | Money market currency funds [Member]
Assets:
Marketable securities, fair value
Level 2 [Member]
Assets:
Cash and equivalents
Cash and equivalents, and marketable securities and investments	3,312
Deferred compensation investments, including life insurance cash surrender value	4,311
Other securities
Total Assets	7,623
Liabilities:
Deferred executive compensation liability	3,206
Deferred development costs
Melphalan license contingent consideration
Contingent value right
Total Liabilities	3,206
Level 2 [Member] | Bank CDs [Member]
Assets:
Marketable securities, fair value	252
Level 2 [Member] | Money market currency funds [Member]
Assets:
Marketable securities, fair value	3,060
Level 3 [Member]
Assets:
Cash and equivalents
Cash and equivalents, and marketable securities and investments
Deferred compensation investments, including life insurance cash surrender value
Other securities
Total Assets
Liabilities:
Deferred executive compensation liability
Deferred development costs	18,651
Melphalan license contingent consideration	4,700
Contingent value right
Total Liabilities	23,351
Level 3 [Member] | Bank CDs [Member]
Assets:
Marketable securities, fair value
Level 3 [Member] | Money market currency funds [Member]
Assets:
Marketable securities, fair value