Product Revenue (Details) (USD $)	3 Months Ended
	Mar. 31, 2013	Dec. 31, 2012
Product revenue
Government rebates, chargebacks and other	$ 5,900,000
Product revenue, net	64,008,000
Deferred revenue	9,322,000	9,811,000
Revenue reserve for Kyprolis
Balance at the beginning of the period	9,939,000
Provision related to current period sales	7,338,000
Credits/ Payments	(7,799,000)
Other	(5,887,000)
Balance at the end of the period	3,591,000
Distribution fees and product returns
Accepted return period for expired product	3 months
Reduction in Medicaid rebate and PHS chargeback (in dollars per share)	$ 0.08
Kyprolis
Product revenue
Product revenue, gross	65,459,000
Government rebates, chargebacks and other	1,651,000
Returns reserve and Distribution fees	(3,102,000)
Product revenue, net	64,008,000
Deferred revenue	9,300,000
Revenue reserve for Kyprolis
Number of product replacement claims received which met the requirements of the program	0
Kyprolis | Chargebacks
Revenue reserve for Kyprolis
Balance at the beginning of the period	5,707,000
Provision related to current period sales	3,919,000
Credits/ Payments	(4,415,000)
Other	(5,087,000)
Balance at the end of the period	124,000
Kyprolis | Rebates and other
Revenue reserve for Kyprolis
Balance at the beginning of the period	1,946,000
Provision related to current period sales	317,000
Credits/ Payments	(51,000)
Other	(800,000)
Balance at the end of the period	1,412,000
Kyprolis | Distribution Fees and Returns
Revenue reserve for Kyprolis
Balance at the beginning of the period	2,286,000
Provision related to current period sales	3,102,000
Credits/ Payments	(3,333,000)
Balance at the end of the period	$ 2,055,000