EXHIBIT 1

JOINT FILING AGREEMENT
 
The undersigned hereby agree to the joint filing of the Schedule 13G to which this Agreement is attached.
 
 
Dated:  February 14, 2011
 
 
 
OBERWEIS ASSET MANAGEMENT, INC.
 
By:      /s/ Patrick B. Joyce                                                                    
     Patrick B. Joyce
     Executive Vice President


JAMES D. OBERWEIS

 
/s/ James D. Oberweis                                                              

 

 
JAMES W. OBERWEIS

/s/ James W. Oberweis