Check out the companies making headlines in after-hours trading

$DexCom (DXCM.US)$ — Shares of the medical device company plunged more than 35%. Dexcom’s fiscal full-year revenue guidance of $4 billion to $4.05 billion marked a reduction from the outlook it shared earlier in the year. Revenue in the second quarter missed analysts’ expectations, coming in at $1 billion versus consensus estimates of $1.04 billion, per LSEG. Insulet shares slipped 9.1% in sympathy.

$Boston Beer (SAM.US)$ – The maker of Twisted Tea and Samuel Adams slid 5% after second quarter results missed the Street’s estimates. Boston Beer posted earnings of $4.39 per share on revenue of $579 million, while analysts sought $5.02 per share in earnings and $597 million in revenue, per LSEG.

$Coursera (COUR.US)$ — Shares of the online course provider surged 16%. Second-quarter revenue came in at $170 million, surpassing analysts’ estimates for $164 million, per LSEG. Coursera posted a loss of 15 cents per share, while the Street called for earnings of one cent per share.