Net Income (Loss) Per Share - Additional Information (Detail)	3 Months Ended		9 Months Ended
	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012
Components Of Income Before Taxes [Line Items]
Shares included in computation of diluted income per share	825,000
Unvested restricted common stock yet not included				70,000
Options to purchase yet not included		1,600,000	1,300,000	1,600,000
Outstanding options to purchase	1,300,000		1,300,000
Restricted Stock [Member]
Components Of Income Before Taxes [Line Items]
Shares included in computation of diluted income per share	23,000	70,000	23,000