Option Activity Under Plan (Detail) - USD ($) $ / shares in Units, shares in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Share Based Compensation Plans [Line Items]
Outstanding	32	35
Granted	20	3
Forfeited	0	(4)
Expired	(15)	(2)
Outstanding	37	32	35
Vested and expected to vest	31	31
Exercisable	15	28
Weighted - Average Exercise Price, Outstanding	$ 232.00	$ 266.00
Weighted - Average Exercise Price, Granted	34.60	150.00
Weighted - Average Exercise Price, Forfeited	0	330.00
Weighted - Average Exercise Price,Expired	267.20	426.00
Weighted - Average Exercise Price, Outstanding	112.60	232.00	$ 266.00
Weighted - Average Exercise Price, Vested and expected to vest	124.60	230.00
Weighted - Average Exercise Price, Exercisable	$ 181.00	$ 214.00
Weighted Average Remaining Contractual Term (In years), Outstanding	7 years 6 months	4 years	5 years 2 months 12 days
Weighted Average Remaining Contractual Term (In years), Granted	9 years 3 months 18 days	9 years 3 months 18 days
Weighted Average Remaining Contractual Term (In years), Vested and expected to vest	7 years 2 months 12 days	3 years 9 months 18 days
Weighted Average Remaining Contractual Term (In years), Exercisable	5 years 1 month 6 days	3 years 3 months 18 days
Aggregate Intrinsic Value, Outstanding	$ 0	$ 2,241
Aggregate Intrinsic Value, Outstanding	0	0	$ 2,241
Aggregate Intrinsic Value, Vested and expected to vest	0	0
Aggregate Intrinsic Value, Exercisable	$ 0	$ 0