Fair Value Measurements (Details 1) (USD $) In Thousands, unless otherwise specified	Mar. 31, 2014	Dec. 31, 2013
Fair Value, Level 1
Fair Value
Cash and Cash Equivalents	$ 46,517	$ 37,499
Short-term Investments	51,298	91,077
Total Cash and Cash Equivalents and Investments	97,815	128,576
Other Long-term Liabilities	0	0
Total Liabilities	0	0
Fair Value, Level 2
Fair Value
Cash and Cash Equivalents	0	0
Short-term Investments	552	552
Total Cash and Cash Equivalents and Investments	552	552
Other Long-term Liabilities	0	0
Total Liabilities	0	0
Fair Value, Level 3
Fair Value
Cash and Cash Equivalents	0	0
Short-term Investments	0	0
Total Cash and Cash Equivalents and Investments	0	0
Other Long-term Liabilities	28,852	27,710
Total Liabilities	28,852	27,710
Fair Value, Total
Fair Value
Cash and Cash Equivalents	46,517	37,499
Short-term Investments	51,850	91,629
Total Cash and Cash Equivalents and Investments	98,367	129,128
Other Long-term Liabilities	28,852	27,710
Total Liabilities	$ 28,852	$ 27,710