NetScout Systems (NTCT) stock is getting crushed in Tuesday's trading. The cybersecurity company's share price was down 19.4% as of 10:30 a.m. ET, according to data from S&P Global Market Intelligence.

After the market closed yesterday, NetScout published preliminary second-quarter results and updated guidance that lowered its full-year performance targets. For the second quarter, the company now expects non-GAAP (adjusted) earnings per share to be between $0.60 and $0.62 on revenue between $195 million and $197 million. Meanwhile, the average analyst estimate had called for the business to post roughly $223 million in sales during the period. 

NetScout's results and guidance are shocking the market

NetScout's preliminary Q2 results came in well below the market's expectations. The company now expects to post revenue between $840 million and $860 this year, while it had previously called for sales to be between $915 and $945 million. Additionally, it cut its adjusted earnings target to between $2 per share and $2.20 per share -- down from previous guidance for per-share earnings between $2.20 and $2.32. Meanwhile, its GAAP earnings forecast was cut to between $0.69 and $0.89 per share -- down from its previous guidance for per-share earnings between $0.86 and $0.98.

What does it mean for NetScout Systems stock?

Based on the midpoint of its new guidance range, NetScout is now calling for sales to decline roughly 7% from the $914.5 million in sales that it recorded in the previous fiscal year. The midpoint of its guidance for adjusted earnings per share also suggests a roughly 2% decline from the per-share earnings of $2.14 it posted last year. 

NetScout is now valued at roughly 10.5 times this year's expected earnings and 1.9 times expected sales, levels that look fairly cheap given that the business has remained solidly profitable. On the other hand, the unexpectedly soft Q2 performance and forward guidance suggests that it could face some significant pressures in the near term.

NetScout saw demand begin to slow in the second quarter, a trend it attributes to capital spending pressures facing the service provider industry and macroeconomic headwinds. The company's management will provide more detailed commentary on these trends and the business at large when it hosts its quarterly conference call before the market opens on Nov. 2.