Consolidated Statements of Stockholders' Equity (Parenthetical) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Exercise of stock options	563	348	184
Employee stock purchase plan sales, shares	89	110	94
Sale of common stock, shares	7,547	4,774	437
Purchases of treasury stock, shares			12
Common Stock [Member]
Exercise of stock options	563	348	184
Employee stock purchase plan sales, shares	89	110	94
Sale of common stock, shares	7,547	4,774	437
Additional Paid-In Capital [Member]
Exercise of stock options	563	348	184
Employee stock purchase plan sales, shares	89	110	94
Sale of common stock, shares	7,547	4,774	437
Purchases of treasury stock, shares			12