Annual report pursuant to Section 13 and 15(d)

Summary of Warrant Activity (Detail)

v3.10.0.1
Summary of Warrant Activity (Detail) - Warrants - $ / shares
shares in Thousands
12 Months Ended
Dec. 31, 2018
Dec. 31, 2017
Dec. 31, 2016
Shares      
Beginning Balance 1,225 2,281 2,018
Granted/Issued 760 785 407
Exercised    
Forfeited, cancelled, or expired (52) (1,841) (144)
Ending Balance 1,933 1,225 2,281
Warrants exercisable, December 31, 2018 1,906    
Weighted-Average Exercise Price Per Share      
Beginning Balance $ 9.65 $ 20.90 $ 20.90
Granted/Issued 2.23 9.00 10.00
Exercised    
Forfeited, cancelled, or expired 2.35 20.00 32.50
Ending Balance 6.62 $ 9.65 $ 20.90
Warrants exercisable, December 31, 2018 $ 6.43