The main point is that the company's market cap increased by...

The main point is that the company's market cap increased by about $18M over the course of the last week. The acquisition would therefore have to be much more substantial and earnings accretive than any of the previous acquisitions to justify such a significant re-rating. To justify the price rise in my opinion, the acquisition would have to be a complementary one in the vicinity of $10-$15M on a lower EBIT multiple than TOX.

If the acquisition is another small company in the $3-$5M range, then i'd argue that the share price (currently at $1.75) has run too hard and should probably fall back slightly in the absence of either a larger than expected half year report, or profit upgrade.