Series C Convertible Preferred Stock Installments (Detail) (USD $) In Thousands, except Share data, unless otherwise specified	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011
Class of Stock [Line Items]
Dividend, installment payments	$ 3,431	$ 3,604
Principal, installment payments	31,120	15,560
Total, installment payments	34,551	19,164
Dividend, cash	2,400	1,362
Principal, cash	23,340	7,780
Total,cash	25,740	9,142
Dividend, stock	1,031	2,242
Principal, stock	7,780	7,780
Total, stock	$ 8,811	$ 10,022
Dividend, stock(shares)	80,169	193,838
Principal, stock(shares)	600,309	672,593
Total, stock(shares)	680,478	866,431