Summary of Significant Accounting Policies - Shares Used in Computing Diluted Net Income (Loss) Per Share (Detail) In Thousands, unless otherwise specified	3 Months Ended
	Mar. 31, 2013	Mar. 31, 2012
Earnings Per Share, Diluted, by Common Class, Including Two Class Method [Line Items]
Weighted average shares used in calculating basic net income (loss) per share	30,630	30,171
Unvested restricted shares and restricted share units		41
Shares used in computing diluted net income (loss) per share	30,630	31,118
Stock options [Member]
Earnings Per Share, Diluted, by Common Class, Including Two Class Method [Line Items]
Stock options and Warrants		905
Warrants [Member]
Earnings Per Share, Diluted, by Common Class, Including Two Class Method [Line Items]
Stock options and Warrants		1