Dexcom (NASDAQ:DXCM) significantly revised its guidance downward after its second-quarter revenue failed to meet expectations, citing weaker execution of essential strategies. Following this announcement, the company's shares plummeted over 36% in pre-market today.

The diabetes management firm adjusted its revenue forecast to a range of $4.00 billion to $4.05 billion, a reduction from the previously anticipated $4.20 billion to $4.35 billion.

Dexcom acknowledged that although it made progress on several key strategic initiatives during the second quarter, its overall execution fell short of its rigorous standards.

For the second quarter, Dexcom reported earnings of $0.43 per share on revenue of $1.00 billion, compared to the analysts' expectations of $0.39 per share on revenue of $1.04 billion.

Looking ahead to the third quarter, the company provided a revenue guidance range of $975 million to $1.00 billion, which is below the Street estimate of $1.15 billion.