In the short time since its initial public offering (IPO) in April, DocuSign (NASDAQ:DOCU) has been on a tear. Priced at $29 ahead of its IPO, shares of the e-signature and cloud-based document company have already surged over 100% above this IPO price. Furthermore, even excluding DocuSign's initial sharp rise on the first day of trading, which put its stock price at $39.73, DocuSign has surged 50%.

Bullishness toward DocuSign heightened last week ahead of the company's first-quarter earnings call as investors bet the company would prove its worth in its first quarter as a publicly traded company. Sure enough, DocuSign did exactly that, reporting rapid revenue growth and continued momentum internationally. Here are some of the key metrics showing how DocuSign's business is impressing investors.

DocuSign's e-signature product on a laptop and smartphone

DocuSign's e-signature product. Image source: DocuSign.

1. An 80% non-GAAP gross margin

One facet of DocuSign's business that likely appeals to many investors is the company's scalability, which has been particularly evident by DocuSign's meaningful growth in its non-GAAP gross profit margin. DocuSign's non-GAAP gross margin was 80% in its first quarter of fiscal 2019, up from 78% in the year-ago quarter. 

A similarly strong trend in DocuSign's non-GAAP gross profit margin is evident on an annual basis. DocuSign's non-GAAP gross margin has improved from 73% in fiscal 2016 to 79% in fiscal 2018. 

2. A non-GAAP operating margin of 3%

Highlighting the operating leverage in DocuSign's business model is its rapidly improving non-GAAP operating margin. DocuSign achieved a non-GAAP operating margin of 3% in its first quarter of fiscal 2019. This is up from a negative operating margin of 7% in the year-ago quarter.

This operating leverage is even more evident on an annual basis, with DocuSign's operating leverage improving from negative 32% in fiscal 2016 to negative 2% in fiscal 2018. 

3. Revenue increased 37% year over year

Another aspect of DocuSign's business worth giving some weight is its sharp growth in revenue. In the company's most recent quarter, revenue was up 37% year over year. This was driven by a 39% year-over-year increase in subscription revenue, which accounted for 95% of total revenue and a 14% increase in professional services and other revenue.

4. Non-GAAP earnings per share was $0.01

This was up from a non-GAAP net loss per share of $0.30 in the year-ago quarter.

5. DocuSign has 404,000 customers

DocuSign's paying customers are impressively up about 30,000 year over year, rising to over 400,000. Of these new customers, 2,000 were enterprise and commercial businesses, which typically have multiyear contracts.

6. International revenue surged 52%

Perhaps one of the most encouraging metrics for DocuSign investors to mull over is the company's international revenue growth. DocuSign's international revenue in its first quarter of fiscal 2019 shot up 52% year over year, management said in the company's quarterly earnings call. Accounting for 17% of total revenue, DocuSign's international segment is large enough for investors to get excited about how it can impact the company's overall growth in the coming years.

Adding fuel to the fire, management said in its earnings call that it is optimistic about its international growth, saying that "the market is very early in terms of penetration" and that there is "a huge opportunity" to expand. 

While DocuSign investors should take note of the stock's pricier valuation after its sharp gain, this is certainly a company worth adding to your watchlist.

Daniel Sparks has no position in any of the stocks mentioned. The Motley Fool has no position in any of the stocks mentioned. The Motley Fool has a disclosure policy.