Carrying Value and Fair Value of Certain Financial Assets and Liabilities Measured at Fair Value on Recurring Basis (Detail) (USD $) In Thousands, unless otherwise specified	Sep. 30, 2013	Dec. 31, 2012
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Cash held in escrow	$ 0	$ 6,434
Restricted marketable securities	5	10
Fair Value, Measurements, Recurring [Member] | Level 1 [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Cash and cash equivalents	108,694	66,029
Cash held in escrow		6,434
Restricted marketable securities	5	10
Available-for-sale securities	32	58
Warrant participations	0	0
Total marketable securities	57,424	140,016
Fair Value, Measurements, Recurring [Member] | Level 2 [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Cash and cash equivalents	0	0
Cash held in escrow		0
Restricted marketable securities	0	0
Available-for-sale securities	0	0
Warrant participations	0	0
Total marketable securities	0	0
Fair Value, Measurements, Recurring [Member] | Level 3 [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Cash and cash equivalents	0	0
Cash held in escrow		0
Restricted marketable securities	0	0
Available-for-sale securities	0	0
Warrant participations	417	423
Total marketable securities	0	0
Fair Value, Measurements, Recurring [Member] | Carrying (Reported) Amount, Fair Value Disclosure [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Cash and cash equivalents	108,694	66,029
Cash held in escrow		6,434
Restricted marketable securities	5	10
Available-for-sale securities	32	58
Warrant participations	417	423
Total marketable securities	57,424	140,016
NuPathe [Member] | Fair Value, Measurements, Recurring [Member] | Common Stock [Member] | Level 1 [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Ownership interest	12,437	8,897
NuPathe [Member] | Fair Value, Measurements, Recurring [Member] | Common Stock [Member] | Level 2 [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Ownership interest	0	0
NuPathe [Member] | Fair Value, Measurements, Recurring [Member] | Common Stock [Member] | Level 3 [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Ownership interest	0	0
NuPathe [Member] | Fair Value, Measurements, Recurring [Member] | Common Stock [Member] | Carrying (Reported) Amount, Fair Value Disclosure [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Ownership interest	12,437	8,897
NuPathe [Member] | Fair Value, Measurements, Recurring [Member] | Preferred stock, warrants and options [Member] | Level 1 [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Ownership interest	0
NuPathe [Member] | Fair Value, Measurements, Recurring [Member] | Preferred stock, warrants and options [Member] | Level 2 [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Ownership interest	0
NuPathe [Member] | Fair Value, Measurements, Recurring [Member] | Preferred stock, warrants and options [Member] | Level 3 [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Ownership interest	2,123
NuPathe [Member] | Fair Value, Measurements, Recurring [Member] | Preferred stock, warrants and options [Member] | Carrying (Reported) Amount, Fair Value Disclosure [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Ownership interest	2,123
NuPathe [Member] | Fair Value, Measurements, Recurring [Member] | Preferred Stock Warrants [Member] | Level 1 [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Ownership interest		0
NuPathe [Member] | Fair Value, Measurements, Recurring [Member] | Preferred Stock Warrants [Member] | Level 2 [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Ownership interest		0
NuPathe [Member] | Fair Value, Measurements, Recurring [Member] | Preferred Stock Warrants [Member] | Level 3 [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Ownership interest		12,075
NuPathe [Member] | Fair Value, Measurements, Recurring [Member] | Preferred Stock Warrants [Member] | Carrying (Reported) Amount, Fair Value Disclosure [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Ownership interest		12,075
Commercial paper [Member] | Fair Value, Measurements, Recurring [Member] | Level 1 [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Total marketable securities	23,749	50,932
Commercial paper [Member] | Fair Value, Measurements, Recurring [Member] | Level 2 [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Total marketable securities	0	0
Commercial paper [Member] | Fair Value, Measurements, Recurring [Member] | Level 3 [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Total marketable securities	0	0
Commercial paper [Member] | Fair Value, Measurements, Recurring [Member] | Carrying (Reported) Amount, Fair Value Disclosure [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Total marketable securities	23,749	50,932
U.S. Treasury Bills [Member] | Fair Value, Measurements, Recurring [Member] | Level 1 [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Total marketable securities	16,181	21,352
U.S. Treasury Bills [Member] | Fair Value, Measurements, Recurring [Member] | Level 2 [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Total marketable securities	0	0
U.S. Treasury Bills [Member] | Fair Value, Measurements, Recurring [Member] | Level 3 [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Total marketable securities	0	0
U.S. Treasury Bills [Member] | Fair Value, Measurements, Recurring [Member] | Carrying (Reported) Amount, Fair Value Disclosure [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Total marketable securities	16,181	21,352
Government agency bonds [Member] | Fair Value, Measurements, Recurring [Member] | Level 1 [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Total marketable securities	2,645	45,909
Government agency bonds [Member] | Fair Value, Measurements, Recurring [Member] | Level 2 [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Total marketable securities	0	0
Government agency bonds [Member] | Fair Value, Measurements, Recurring [Member] | Level 3 [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Total marketable securities	0	0
Government agency bonds [Member] | Fair Value, Measurements, Recurring [Member] | Carrying (Reported) Amount, Fair Value Disclosure [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Total marketable securities	2,645	45,909
Certificates of deposit [Member] | Fair Value, Measurements, Recurring [Member] | Level 1 [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Total marketable securities	14,849	21,823
Certificates of deposit [Member] | Fair Value, Measurements, Recurring [Member] | Level 2 [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Total marketable securities	0	0
Certificates of deposit [Member] | Fair Value, Measurements, Recurring [Member] | Level 3 [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Total marketable securities	0	0
Certificates of deposit [Member] | Fair Value, Measurements, Recurring [Member] | Carrying (Reported) Amount, Fair Value Disclosure [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Total marketable securities	$ 14,849	$ 21,823