Collaboration, License and Purchase Agreements - Narrative 2 (Details) (USD $)	12 Months Ended				1 Months Ended	12 Months Ended			1 Months Ended
	Dec. 31, 2012 Durect Development and License Agreement [Member]	Dec. 31, 2011 Durect Development and License Agreement [Member]	Dec. 31, 2011 Durect Development and License Agreement [Member] Minimum [Member]	Dec. 31, 2011 Durect Development and License Agreement [Member] Research and Development Expense [Member]	May 31, 2012 Alkermes License Agreement (formerly Elan Pharma International Limited) [Member]	Dec. 31, 2012 Alkermes License Agreement (formerly Elan Pharma International Limited) [Member]	Dec. 31, 2011 Alkermes License Agreement (formerly Elan Pharma International Limited) [Member] Approval of Manufacturing Facility [Member]	Dec. 31, 2011 Alkermes License Agreement (formerly Elan Pharma International Limited) [Member] Approval of Product [Member]	May 31, 2012 Alkermes License Agreement (formerly Elan Pharma International Limited) [Member] Research and Development Expense [Member]	Aug. 30, 2011 Alkermes License Agreement (formerly Elan Pharma International Limited) [Member] Research and Development Expense [Member]	Nov. 30, 2007 Alkermes License Agreement (formerly Elan Pharma International Limited) [Member] Research and Development Expense [Member]
Research and Development Arrangement, Contract to Perform for Others [Line Items]
Non-refundable up-front payment				$ 2,250,000							$ 500,000
Milestone payments									1,000,000	750,000
Minimum future milestone payments		103,000,000			2,750,000
Annual external development expense obligation			1,000,000
External development expense obligation period	12 months
Contingent payment included In minimum future milestone payments							$ 750,000	$ 2,000,000
Royalty agreement term	15 years					15 years
Automatic extension of arrangement term						3 years
Agreement termination notice period						12 months