"Firms that generate a free cash flow margin (free cash flow divided by total revenue) above 5% are usually considered cash cows. Intuitive Surgical's free cash flow margin has averaged about 32% during the past 3 years."
The SeekingAlpha article was titled "A Nearly $700 Price Tag For Intuitive Surgical? "
I'll try posting a link to the full article as a reply to this post but I'm not sure it will let me.
Full Disclosure: the article makes the case that ISRG is fairly valued at current levels but makes a plausible case for higher valuation as well.