Significant Accounting Policies (Details 2) (USD $) In Thousands, unless otherwise specified	Jun. 30, 2013	Dec. 31, 2012
Summary of receivables
Total receivables	$ 1,024	$ 4,562
U.S. Department of Health and Human Services [Member]
Summary of receivables
Total receivables	933	4,038
Shionogi & Co. Ltd. [Member]
Summary of receivables
Total receivables	91	524
Billed [Member]
Summary of receivables
Total receivables	388	674
Billed [Member] | U.S. Department of Health and Human Services [Member]
Summary of receivables
Total receivables	297	150
Billed [Member] | Shionogi & Co. Ltd. [Member]
Summary of receivables
Total receivables	91	524
Unbilled [Member]
Summary of receivables
Total receivables	636	3,888
Unbilled [Member] | U.S. Department of Health and Human Services [Member]
Summary of receivables
Total receivables	636	3,888
Unbilled [Member] | Shionogi & Co. Ltd. [Member]
Summary of receivables
Total receivables