As Chinese smartphone maker Xiaomi reportedly preps a 2018 IPO in which it wants to raise over $10 billion, it's worth remembering exactly when the company last did a big capital raise, and what happened shortly afterwards.

In late 2014, Xiaomi raised $1.1 billion at an eye-popping $46 billion valuation. Investors included Singapore's sovereign wealth fund, Russian investment firm DST Global and a PE firm affiliated with Alibaba (BABA - Get Report) chairman Jack Ma.

The company has set its sights even higher this year: The Wall Street Journal reports Xiaomi is aiming to go public in Hong Kong (and perhaps also Shanghai) in the second half of 2018 at a valuation somewhere between $80 billion and $100 billion. Public investors will, of course, have the final say on just what Xiaomi's post-IPO valuation is.

What allowed an Android OEM whose sales skew towards sub-$500 models to receive a $46 billion valuation in 2014? Xiaomi's sales were skyrocketing at the time, as the company's viral marketing, direct sales efforts, custom Android interface (known as MIUI) and knack for creating phones with high-end specs and mid-range prices yielded strong demand among younger Chinese consumers.

In 2014, the company's phone shipments rose an astounding 227% to 61.1 million, making it the world's fifth-biggest smartphone vendor after Samsung (SSNLF) , Action Alerts Plus holding Apple  (AAPL - Get Report) and Chinese peers Huawei and Lenovo.

But Xiaomi's momentum began slowing in 2015 as Chinese smartphone growth slowed and domestic rivals -- not just Huawei and Lenovo, but also upstarts such as Oppo and Vivo -- began replicating many of the company's tactics. Xiaomi said it shipped "over 70 million" phones in 2015, falling short of an original target of 80 million. Revenue rose a mere 3% in dollars to $12.5 billion. Research firm IDC believes Xiaomi's phone shipments rose 10% annually in Q4 2015, a far cry from the 179% growth IDC believes Xiaomi saw a year earlier.

And things really went downhill in 2016. Xiaomi declined to share its phone sales for the year, but research firm IDC believes they fell 25% to 53 million, knocking the company out of the global top five. The decline was likely even larger in China, given that Xiaomi's Indian phone shipments rose 150% in 2016.

But things look a lot better today. Xiaomi disclosed in January it had topped its 2017 revenue target of RMB100 billion ($15.8 billion) -- Reuters reported in December the company had told bankers the target could be topped by as much as 18% -- and claimed it can "do much more" in revenue in 2018. IDC believes the company's smartphone shipments, lifted both by a rebound in China and rising sales to markets such as India, Russia and Indonesia, rose 75% to 92.4 million.

Xiaomi's 2017 growth wasn't merely driven by smartphone sales, however. The company says revenue for its Mijia brand, which covers a number of consumer electronics and smart home/IoT devices, hit roughly $3 billion last year. Aided by a sizable retail store footprint, Xiaomi also now sells everything from laptops to TV sets to Bluetooth headsets, and has an online services business that includes a video streaming service, a gaming platform and a lending service.

And the company is starting to get serious about trying to crack affluent Western markets. Xiaomi began selling phones in Spain in late 2017 (its Mi Mix 2 high-end phone launched around the same time), and recently said it plans to enter the U.S. in late 2018 or early 2019. National security worries could get in the way of the U.S. effort, however; in January, Huawei saw a deal with AT&T (T - Get Report)  to sell its high-end Mate 10 phone cancelled at the last minute due to security concerns.

But even if Xiaomi can sidestep that issue, becoming a top smartphone OEM in the U.S. and other developed markets presents a unique set of challenges. Sales here skew more towards the high end, and no one to date has put a massive dent in Apple and Samsung's dominance within this segment. Chalk this up to the continued popularity of the iPhone (and the software/services ecosystem surrounding it), Samsung's success at launching phones with top-notch displays and cameras, and the importance of branding and marketing in winning over high-end buyers.

In addition, as impressive as the company's recent growth has been in emerging markets, it's worth asking just how much of a long-term moat Xiaomi has created. The company likes to argue its various hardware offerings are part of a broader ecosystem, but Samsung, Huawei and other big mobile OEMs can also claim extensive consumer electronics and smart home lineups.

MIUI and Xiaomi's online services do provide a measure of differentiation, but in the end, the company is relying on the same OS as its rivals (Apple excluded). And it's one for which Action Alerts Plus holding Alphabet/Google's (GOOGL - Get Report) apps and services are ubiquitous outside of China, and for which Tencent's WeChat app is a platform unto itself within China.

Xiaomi's focus and execution -- not just in terms of product development, but also in terms of its sales and marketing efforts -- have allowed it to get pretty far. But just as the company raised funds in 2014 just before its sales growth began slowing sharply, it might be rushing to go public this year just before its latest sales surge loses steam.