RegEx for Money greater than $0?

 I'm not very good with RegEx, but I'm trying to find an expression that will validate a USD amount, greater than zero, that will allow comma's but they're not required.  Any idea how to do this? 
For example:
.01      = true
1         = true
1.00    = true
1,000  = true
1000   = true

0         = false
-1        = false
.001    = false
I found this one, but it allows $0.  Any help is appreciated.
[0-9]+(,[0-9]{3})*(\.[0-9]{2})?$

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