Annual report pursuant to Section 13 and 15(d)

Common Stock - Summary of Restricted Stock Unit Award Activity (Detail)

v3.6.0.2
Common Stock - Summary of Restricted Stock Unit Award Activity (Detail) - Restricted Stock Unit [Member] - $ / shares
12 Months Ended
Dec. 31, 2016
Dec. 31, 2015
Dec. 31, 2014
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]      
Number of Shares, Beginning Balance 640,759 680,201 356,589
Number of Shares, Granted   249,775 814,800
Number of Shares, Vested (217,296) (269,401) (199,887)
Number of Shares, Forfeited or expired (170,242) (19,816) (291,301)
Number of Shares, Ending Balance 253,221 640,759 680,201
Weighted-Average Grant Date Fair Value, Beginning Balance $ 4.92 $ 7.34 $ 12.06
Weighted-Average Grant Date Fair Value, Granted   1.92 6.48
Weighted-Average Grant Date Fair Value, Vested 5.23 8.08 7.00
Weighted-Average Grant Date Fair Value, Forfeited or expired 5.07 7.27 10.93
Weighted-Average Grant Date Fair Value, Ending Balance $ 4.56 $ 4.92 $ 7.34