Investments (Tables)

6 Months Ended

Jun. 30, 2013

Investments, Debt and Equity Securities [Abstract]

Schedule of Investments

At June 30, 2013 investments were as follows:

	Cost		Gross Unrealized Gains		Gross Unrealized Losses		Fair Value
Debt Securities:
U.S. treasury securities	$	84,964	$	18	$	—	$	84,982
Corporate debt securities	30,446		—		909		29,537
	$	115,410	$	18	$	909	$	114,519

Contractual Maturities of Investments

At June 30, 2013, the contractual maturities of investments classified as available-for-sale were as follows:

	Cost		Fair Value
Due in one year or less	$	84,964	$	84,982
Due after one year through five years	16,728		16,343
Due after five years through ten years	13,718		13,194
	$	115,410	$	114,519