Condensed Consolidated Balance Sheets (Parenthetical) - $ / shares	Sep. 30, 2016	Dec. 31, 2015
Condensed Consolidated Balance Sheets
Common stock, par value (in dollars per share)	$ 0.001	$ 0.001
Common stock, shares authorized (in shares)	50,000,000	50,000,000
Common stock, shares issued (in shares)	45,562,013	45,124,948
Common stock, shares outstanding (in shares)	34,615,466	34,394,412
Treasury stock, shares (in shares)	10,946,547	10,730,536