Equity Compensation Plans - Stock Options Granted, Forfeited, Exercised and Expired (Detail) - USD ($) $ / shares in Units, $ in Thousands		3 Months Ended
		Mar. 31, 2016	Mar. 31, 2015
Number of shares
Number of Shares, Outstanding at beginning of period		1,088,208
Number of Shares, Granted		159,000	0
Number of Shares, Forfeited		0
Number of Shares, Exercised		0	0
Number of Shares, Expired		(188,500)
Number of Shares, Outstanding at end of period		1,058,708
Number of Shares, Exercisable at end of period		736,061
Weighted Average Exercise Price
Weighted Average Exercise Price, Outstanding at beginning of period		$ 70.21
Weighted Average Exercise Price, Granted		3.57
Weighted Average Exercise Price, Forfeited		0
Weighted Average Exercise Price, Exercised		0
Weighted Average Exercise Price, Expired		121.56
Weighted Average Exercise Price, Outstanding at end of period		51.06
Weighted Average Exercise Price, Exercisable at end of period		$ 69.17
Aggregate Exercise Price
Aggregate Exercise Price, Outstanding at beginning of period		$ 76,405
Aggregate Exercise Price, Granted		568
Aggregate Exercise Price, Forfeited		0
Aggregate Exercise Price, Exercised		0
Aggregate Exercise Price, Expired		(22,914)
Aggregate Exercise Price, Outstanding at end of period		54,059
Aggregate Exercise Price, Exercisable at end of period		$ 50,913
Weighted Average Remaining Contractual Term
Weighted Average Remaining Contractual Term, Outstanding at end of period, years		1 year 10 months 24 days
Weighted Average Remaining Contractual Term, Exercisable at end of period, years		1 year 8 months 12 days
Aggregate Intrinsic Value
Aggregate Intrinsic Value, Outstanding at end of period	[1]	$ 0
Aggregate Intrinsic Value, Exercisable at end of period	[1]	$ 0

[1] The aggregate intrinsic value of the stock options was calculated by identifying those stock options that had a lower exercise price than the closing market price of our common stock on March 31, 2016 and multiplying the difference between the closing market price of our common stock and the exercise price of each of those stock options by the number of shares subject to those stock options that were outstanding or exercisable, as applicable. Since the closing market price of our common stock on March 31, 2016 was lower than the exercise price of all outstanding stock options and exercisable stock options, the aggregate intrinsic value of the stock options was zero.