Correct; the inputs are bases of NPN transistors, and the OTA saturates unl ess you bias both with net input current.
_diode and the lack of positive current into one input.
The current into the (+) input comes from the 'compensation' diode, minus s ome PNP emitter current.
Positive current from the (+) compensation diode, not from the (+) input pi n. Net current positive.
I think this is mainly confusing because we are accustomed to op amps, wher e input voltages balance; the input voltages on an OTA which is actually delivering current (to the circular terminal on the rightmost 1M resistor) are going to differ by few-to-dozens of millivolts. The multiplication output signal comes from that small imbalance.