Assets and Liabilities Measured at Fair Value (Details) (USD $)	3 Months Ended		146 Months Ended			1 Months Ended	3 Months Ended	1 Months Ended																						3 Months Ended
	Mar. 31, 2014	Mar. 31, 2013	Mar. 31, 2014	Dec. 31, 2013	Dec. 31, 2012	Nov. 30, 2013 Callidus	Mar. 31, 2014 Callidus	Nov. 30, 2013 Maximum Callidus	Mar. 31, 2010 SPA	Mar. 31, 2014 Level 1	Dec. 31, 2013 Level 1	Mar. 31, 2014 Level 2	Dec. 31, 2013 Level 2	Mar. 31, 2014 Level 2 Corporate debt securities	Dec. 31, 2013 Level 2 Corporate debt securities	Mar. 31, 2014 Level 2 Commercial paper	Dec. 31, 2013 Level 2 Commercial paper	Mar. 31, 2014 Level 2 Certificate of deposit	Dec. 31, 2013 Level 2 Certificate of deposit	Mar. 31, 2014 Level 3	Dec. 31, 2013 Level 3	Mar. 31, 2014 Total	Dec. 31, 2013 Total	Mar. 31, 2014 Total Corporate debt securities	Dec. 31, 2013 Total Corporate debt securities	Mar. 31, 2014 Total Commercial paper	Dec. 31, 2013 Total Commercial paper	Mar. 31, 2014 Total Certificate of deposit	Dec. 31, 2013 Total Certificate of deposit	Mar. 31, 2014 2013 Loan Agreement	Mar. 31, 2014 2013 Loan Agreement Level 3 Maximum
Assets and Liabilities Measured at Fair Value
Transfer of assets from Level 1 to Level 2	$ 0		$ 0
Transfer of assets from Level 2 to Level 1	0		0
Change in fair value of warrant liability		262,000	(2,461,000)
Warrant liability		1,200,000
Financial assets and liabilities subject to fair value measurements
Fair value of contingent payment																														300,000
Contingent success fee payable																				273,000	264,000	273,000	264,000							273,000	400,000
Period of trigger event within which success fee is payable																														6 months
Period of effectiveness of trigger event from closing of loan																														5 years
Contingent success fee payable
Balance at the beginning of the period																				273,000	264,000	273,000	264,000							264,000	400,000
Change in fair value																														9,000
Balance at the end of the period																				273,000	264,000	273,000	264,000							273,000	400,000
Additional payment to be made upon achievement of clinical milestone								35,000,000
Additional payment to be made upon achievement of regulatory approval								105,000,000
Maximum merger consideration to be transferred						130,000,000
Contingent consideration payable
Balance at the beginning of the period	10,600,000						10,600,000													11,105,000	10,600,000	11,105,000	10,600,000
Change in fair value	505,000		505,000				505,000
Balance at the end of the period	11,105,000		11,105,000			10,600,000	11,105,000													11,105,000	10,600,000	11,105,000	10,600,000
Proceeds from issuance of warrants									3,300,000
Assets:
Cash/money market funds	27,533,000	26,736,000	27,533,000	43,640,000	33,971,000					27,533,000	43,640,000											27,533,000	43,640,000
Fair value of assets										27,533,000	43,640,000	44,121,000	38,360,000	31,573,000	30,812,000	12,198,000	7,198,000	350,000	350,000			71,654,000	82,000,000	31,573,000	30,812,000	12,198,000	7,198,000	350,000	350,000
Liabilities:
Secured debt												14,415,000	14,473,000									14,415,000	14,473,000
Contingent success fee payable																				273,000	264,000	273,000	264,000							273,000	400,000
Contingent consideration payable	11,105,000		11,105,000			10,600,000	11,105,000													11,105,000	10,600,000	11,105,000	10,600,000
Fair value of liabilities												$ 14,415,000	$ 14,473,000							$ 11,378,000	$ 10,864,000	$ 25,793,000	$ 25,337,000