Summary of Option Activity (Detail) shares in Thousands	3 Months Ended
	Mar. 31, 2020 $ / shares shares
Shares
Beginning Balance | shares	1,287
Granted at fair market value | shares	20
Forfeited, cancelled, or expired | shares	(32)
Ending Balance | shares	1,275
Options exercisable at March 31, 2020 | shares	1,061
Vested options expired during the quarter ended March 31, 2020 | shares	17
Weighted-Average Exercise Price
Beginning Balance | $ / shares	$ 5.77
Granted at fair market value | $ / shares	0.77
Forfeited, cancelled, or expired | $ / shares	8.87
Ending Balance | $ / shares	5.61
Options exercisable at March 31, 2020 | $ / shares	6.35
Vested options expired during the quarter ended March 31, 2020 | $ / shares	$ 13.2
Weighted-Average Remaining Contractual Term (Years)
Options outstanding	5 years 8 months 4 days
Options exercisable	5 years 1 month 9 days