Debt - Additional Information (Detail) (USD $)	1 Months Ended	3 Months Ended			1 Months Ended		1 Months Ended	3 Months Ended
	Mar. 31, 2009	Mar. 30, 2014	Sep. 30, 2013	Dec. 31, 2013	Mar. 31, 2009 Maximum	Mar. 30, 2014 Maximum	Apr. 30, 2009 4.50% Convertible Senior Notes Due March 15, 2014	Mar. 30, 2014 4.50% Convertible Senior Notes Due March 15, 2014
Debt Instrument
Borrowings from local bank	$ 10,000,000
Term of loan, years	5 years
Debt instrument, interest rate, stated percentage	0.80%						4.50%
Loan collateralized by real estate mortgage	6,000,000
Unsecured loan	4,000,000
Semiannual principal payments of loan		1,000,000	1,000,000
Aggregate principal amount				189,998,000			190,000,000
Initial debt conversion price							$ 5.4750
Conversion rate in number of shares							182.65	131.95
Additional aggregate principal amount							1,000
Senior notes maturity date							Mar. 15, 2014
Number of shares excluded for conversion rate calculation								50.7
Trading days used to determine average price per share								25 days
Average trading price of common shares								$ 19.74
Payments of long-term debt		$ 190,975,000						$ 190,000,000
Stock issued in conversion of notes								25,100,000
Stock received and retired								25,100,000
Strike price per share of warrant		$ 7.6650
Warrants settled on a daily basis		534,000
Warrant settlement period		65 days
Common stock shares issuable upon exercise of the warrants						34,526,500
Percentage of warrant price in excess of closing price of common stock					19.99%