Commitments (Details 3) (USD $) In Millions, except Share data, unless otherwise specified	1 Months Ended	12 Months Ended	63 Months Ended
	Jun. 30, 2012	Dec. 31, 2012	Dec. 31, 2012
Development of avanafil under Development, Licensing and Supply Agreement | Mitsubishi Tanabe Pharma Corporation or MTPC
Agreements
Payments made			$ 13.0
Milestone payment paid	3.0
Cost of finished goods inventory purchased		7.4
Threshold sales level for milestone payments		250.0
Terms of agreement		10 years
Potential future milestone payments upon the obtainment of first regulatory approval		2.0
Potential future milestone payments upon the achievement of threshold sales		6.0
Development of Combination Therapy under Assignment Agreement
Agreements
Payments made to date			$ 1.2
Options issued to purchase common stock (in shares)		60,000