CONDENSED CONSOLIDATED BALANCE SHEETS (Parenthetical) (USD $) In Thousands, except Per Share data, unless otherwise specified	Jun. 30, 2011	Dec. 31, 2010
CONDENSED CONSOLIDATED BALANCE SHEETS
Accounts receivable, allowances (in dollars)	$ 301	$ 398
Convertible Senior Notes due 2016, interest rate (as a percent)	4.75%
Common stock, par value (in dollars per share)	$ 0.001	$ 0.001
Common stock, shares authorized	100,000	100,000
Common stock, shares issued	31,980	32,624
Common stock, shares outstanding	31,980	32,624