Although we don't believe in timing the market or panicking over market movements, we do like to keep an eye on big changes -- just in case they're material to our investing thesis.

What: Shares of HealthStream (NASDAQ:HSTM), an Internet-based talent management company that provides learning solutions to the health care industry, jumped as much as 16% after the company reported its second-quarter earnings results.

So what: For the quarter, HealthStream reported revenue growth of 24% to $31.9 million as EPS matched the year-ago quarter's total of $0.09 despite an 8% increase in EBITDA. HealthStream's results matched the Street on EPS at $0.09, but slightly topped the $31.4 million in revenue analysts had expected. Overall, its learning and talent management segment saw revenue climb by 30% as subscription revenue jumped 28%. More importantly, HealthStream boosted its full-year revenue growth forecast to a range of 23% to 25% from previous estimates of 20% to 22% growth. This would imply full-year revenue of $127.6 million to $129.6 million compared to current Street expectations that call for $126.5 million in revenue.

Now what: This was another good earnings report for HealthStream, but I'd really struggle to call it great and worthy of up to a 16% pop in its share price. As I noted in April, the company's business model makes a lot of sense on paper, and its subscription-based service should result in a recurring revenue model that drives free cash flow generation. On the other hand, at 75 times forward earnings, we're looking at a company that has zero room for error. Eventually, its growth rate is going to slow, and when that happens this lofty valuation may not hold up.