After traveling with CFO Michael Sheridan, William Blair analyst Justin Furby is "incrementally more bullish" on DocuSign's fundamentals. The tone was bullish, with a focus on sustaining high growth in a market opportunity that is "uniquely unbound by customer size," Furby tells investors in a research note. Management stands by its four- to five-year view of 20%-25% non-GAAP operating margin that it discussed at its initial public offering, and it described very stable pricing trends that help drive mid-80s non-GAAP subscription gross margin, adds the analyst. Furby sees a path for the company to grow subscription revenue 25% or higher over the next three to five years. He continues to recommend DocuSign as a core holding with an Outperform rating.