What a long, strange week it's been for InvenSense (INVN). And I'm not so sure the weirdness will subside anytime soon.

First, the company reported second-quarter results on Tuesday. Earnings of $0.16 per share and revenue of $55.3 million were right in line with analyst targets, but third-quarter revenue guidance fell short of Street targets by roughly 2%.

InvenSense's motion sensor sales largely ebb and flow in a seasonal pattern, because most of them go into gaming systems that sell like hotcakes over the holidays. More specifically, InvenSense is a pretty good proxy for sales of the Nintendo (NTDOY -1.25%) Wii console, which is fading out as its successor launches next month. The company hopes to show up in smartphones and tablets one of these days, but that's not a significant market yet.

So that small guidance gap is most certainly not why InvenSense shares plunged as much as 20% that night, though. Steven Nasiri, the company's founder and longtime CEO, also announced his immediate resignation from his posts as CEO and chairman of the board.

That's a bit of a bombshell.

Kaboom!
Nasiri will remain on InvenSense's payroll through the end of the year to help smooth out the transition to new CEO Behrooz Abdi. There's no word on why Nasiri is heading out, though he did say he's not planning to start another company at this time.

This sounds less like Nasiri's choosing to move on and more like the board of directors is forcing his hand. When analysts asked him directly on the earnings call, Nasiri seemed tongue-tied and handcuffed:

Well, the press release has already summarized what we can -- we would like to say publicly. Fundamentally [I've reached my goals here and] the board had felt that for the next stage of the company, it's perhaps time to transition to a new CEO. [Abdi is great.] That's all I can basically add.

Abdi comes with a solid pedigree of high-level positions at NetLogic until Broadcom (NASDAQ: BRCM) bought that company, Qualcomm (QCOM -0.20%), and Motorola, but his CV doesn't quite scream "I'm your next CEO!" in my face.

So InvenSense shareholders are left guessing at what goes on behind the curtain, and investors generally hate uncertainty.

Where do we go from here?
The long-term story is still intact: InvenSense is a leader in the motion-sensor market ahead of much larger generalist STMicroelectronics (STM 1.09%), and the technology seems like a natural fit for smartphones and several other markets that InvenSense really hasn't cracked yet. So buying shares now is an early bet on a top performer in a young growth market.

But we don't know what's up with Nasiri's exit. Is there a scandal to cover up? Did Nasiri lose his passion for the company? Any of these options would be terrible for InvenSense in the long run, because there'd be undiscovered cracks in the company's very foundation.

On the other hand, it could be a simple personality clash where Nasiri just held a losing hand. Tough luck, and everybody just moves on. Or perhaps Abdi convinced the rest of the board that he's a much better man for the CEO job right now. In that case, the final outcome depends on whether he's right or not.

My tea leaves and tarot cards failed to unwind this mystery so far, and the Magic 8-Ball keeps saying "Try again later." Like I said, the weirdness will continue until we know more about this boardroom drama. For now, InvenSense is a very interesting stock that certainly belongs on your Foolish watchlist -- but I would hesitate to either buy or sell shares based on this week's action.

In other words, hold your horses, dear Fool.