Since its IPO nearly five years ago, Acme Packet (NASDAQ:APKT) has risen from $17 to as high as $75.69 last month — that’s a nice 37% compound annual growth rate for shares of this maker of communications gear.

In the last month, this high-flyer’s stock has fallen 10% — is this a chance to get in at a cheaper price?

Acme Packet’s so-called session border controllers (SBCs) let groups of people in different locations conduct voice and video communications sessions across their networks. Acme Packets’ customers include service providers, businesses, government agencies and contact centers.

The company has made a good living selling SBCs. In the last five years, sales have grown at a 45% average annual rate to $254 million, leading to a $4.9 billion market capitalization. And in the last 12 months it earned $48 million — with a solid 19% net margin.

Not only that, but Acme Packet is generating cash with a secure balance sheet. It has no long-term debt and its cash has grown at a 17.9% annual rate.

Acme Packet is a leader in a fast growing market. According to Exact Ventures, the business SBC market grew 55% in the year ended last March. This growth is a result of organizations buying new SBC technologies — specifically so-called SIP trunk and hosted unified communications (UC) services.

Acme Packet leads in two big segments — companies and communications service providers. Cisco Systems (NASDAQ: CSCO) is in second place, followed by some smaller competitors. However, since the industry remains fragmented — with 20 competitors — price competition is intense.

In the first quarter of 2011, Acme Packet delivered a strong performance, but it was below Wall Street expectations. Its revenue rose 44.9% to $74 million and its net income was up 65.1% to $13.7 million. But its 19 cents a share EPS was short of the 25 cents mean analyst EPS estimate.

Acme Packet remains confident of its future. After all, in June it signed a lease to boost its Bedford, Mass.-headquarters space — where it does research and development, final test and assembly — by 75% to 262,000 square feet. 443 of its 679 employees work there. And Acme Packet has already hired 70 workers and plans to add 117 more by the end of 2011.

But is Acme Packet boosting its return on capital? In a nutshell, yes. After all, it’s producing positive EVA Momentum, which measures the change in “economic value added” (essentially, profit after deducting capital costs) divided by sales. In 2010, Acme’s EVA Momentum was up a whopping 10%, based on 2009 revenue of $142 million and EVA rising to $10.4 million from -$3.3 million in 2009.

But the stock is really expensive — trading  at a price-to-earnings-to-growth ratio of 2.15 (where 1.0 is considered fairly valued). Acme Packet’s P/E is 91.7 on earnings expected to climb 42.6% to $1.27 a share in 2012.

And if insider selling is any indication, Acme Packet executives have concluded that it’s time to lighten up. For example, CEO Andy Ory — he owns around 4.3 million shares — sold 90,000 shares on June 16. That was way more than the 50,000 he sold the previous month — and he’s been selling shares every month since the beginning of 2011.

This is a good company that investors have noticed. At this high of a PEG, it would need to fall much further while outperforming expectations to make its stock a good investment. If Acme Packet’s CEO thought it could do that, he might be buying shares rather than selling them.

Peter Cohan has no financial interest in the securities mentioned.