Panera's (PNRA) stock has "had a monster move" in the last year and could go still higher, but now may not be the best time to buy it, according to Jim Cramer, TheStreet's founder and manager of the Action Alerts PLUS portfolio, which owns Panera.

The restaurant chain has seen its shares rise from a 52-week-low of about $165 per share to its recent close of $215 per share on Friday. It was trading at $215.18 in mid-day trading on Monday.

"This was our stock pick of the year for Action Alerts ... so far we're doing pretty well," Cramer said.

Cramer added a caveat, however: "If you haven't bought it yet, maybe you want to wait to see what the quarter is, because sometimes these stocks can trade erratically. It's a very thin stock."

In light of food safety issues at Panera's fast casual rival, Chipotle (CMG) - Get Report, Cramer noted that "Panera to some degree has been a beneficiary of Chipotle's problems."

But there are more important reasons to invest in the food chain, long-term.

"Panera is engaged in a multi-year transformation called Panera 2.0, and when you see these transformations, when you see more digital get-in, more technology get-in, it has been terrific," he said.

Panera is "a multi-year story given the fact that it is a multi-year roll-out of tech," Cramer explained.

When Panera reports its first quarter results, investors will look to see whether it can continue its same store sales growth, an important measure of a retailer's health.

It previously said on Feb. 9 that for the first 41 days of its first quarter, comparable sales were up 6.4%, after seeing same store sales up 3.6% in the fourth quarter.

Analysts at Jefferies are predicting that Panera's same-store sales will increase 5% at company-owned locations and  2.5% at franchised locations.

Analysts have estimated earnings of $1.50 per share on revenue of about $670 million for the first three months of 2016. Panera reported earnings of $1.41 per share on revenue of nearly $650 million for the same period a year prior.

Also according to a prior report, Panera has a "buy" rating and a letter grade of A- at TheStreet Ratings because of the company's revenue growth, largely solid financial position with reasonable debt levels by most measures, notable return on equity, solid stock price performance and good cash flow from operations.