From a drive-by glance, it is tempting to dismiss the new GlaxoSmithKline building at the sedate, manicured Navy Yard as a fancy variation on standard office-park fare. Stretched long and low, its mass is broken up by a central atrium, its blue-glass skin as slick as a skating rink. That bulging west facade appears to be a wan attempt by New York's Robert A.M. Stern Architects to punch things up with Gehry-style curves and swoops.

There's some truth here. But like many snap judgments, it is a superficial reading of a design that has huge implications for Philadelphia's downtown, and for office districts everywhere. Glaxo's new Philadelphia home, which replaces offices in a Center City high-rise at 16th and Vine Streets, would be better described as a boho loft space in conventional corporate clothing. It's a social disrupter that promises to shake up the way we work, as well as our cities.

You know you're not in the usual Big Pharma bunker as soon as you step inside the atrium and are blasted with natural light and jelly-bean colors. Immediately to your right, a curving glass wall reveals an open-plan space arranged with identical white worktables. That's where the company president sits. Except when she is curled up with her laptop on one of the very-berry space-age wing chairs in the atrium, or holding a meeting at a table in the cafe.

It's not just Deirdre Connelly, Glaxo's top Philadelphia-based executive, who gets to work where she pleases. Anyone can. The interiors of the four-story building were designed to replicate the sort of grown-up-free zone we've come to expect from creative companies like Google and Facebook. Employees float around like squatters, occupying any table or sofa that catches their fancy. If they need to shut out the world, they can duck into a closet-sized workroom.

The only place where Glaxo employees can't work is in a cubicle. There is not a single one of those gridded work spaces to be found in this freewheeling environment. More radical, no one, not even Connelly, has an office or an assigned desk. Like everyone else, she stores her stuff in one of the candy-colored lockers that resemble kindergarten cubbies. Being untethered from a corner office, Connelly says, means "we can make decisions faster because we see each other. My e-mail has dropped in half."

This approach to office design is known as "hoteling," and it has been adopted mainly by companies whose employees spend most of their time away from the mother ship. Hoteling means companies can rent smaller offices - and, as some cynics might say, pass the cost of space on to their employees. Glaxo has nudged the concept in a more interesting direction.

Glaxo employees can also work off-site if they choose - unlike Yahoo's newly office-bound staff. But the company says the real aim of its new design is to make people want to come to the office.

Glaxo's interior design, which is the work of architect John B. Campbell of Philadelphia's Francis Cauffman, is calibrated to reflect that evolution in office culture. The interiors are, first and foremost, social spaces, where collaboration can occur on a variety of scales - from intimate cafes and lounges, to group worktables and large conference rooms.

When Glaxo first announced it was leaving Center City in 2010, creating a progressive work environment didn't seem to be its main objective. The company, which was founded in Philadelphia, had merged with a British pharmaceutical giant. For a while it looked like the new company might abandon the city altogether, dispatching its rump staff to lab buildings in the suburbs.

Ultimately, Glaxo decided to keep a foot in Philadelphia, but dramatically slashed its rented space, from a high of 800,000 square feet to just 208,000 at the Navy Yard, said John Gattuso of Liberty Property Trust, which developed and owns the new building. (The project received no tax breaks.) Given that Glaxo's 1,350 employees are now ensconced in just 25 percent of their old space, it was remarkable how spacious the building felt on the day I visited.

Getting rid of the desks and offices is part of it. Stern's architects, led by Meghan McDermott, ensured that everyone gets generous gulps of sunlight by breaking up the building into four distinct volumes. Their odd angles actually have a purpose, to deflect glare or increase light. (The curved facade references the Navy ships still docked at the yard.) On the top floor, the roof angles up, giving the space the feeling of an atelier. The same team that produced Glaxo also designed the Comcast tower, and you can see some family resemblance.

Campbell notes that the building still has many more "seats" than people, and that 30 percent of the space is devoted to amenities. Most orbit around the atrium like a town square. There's a cafe, convenience store, fitness center, and, in a nod to Apple, Glaxo's version of the Genius Bar, to provide tech support. The result is, essentially, a purpose-built version of the free-floating world of independent workers, who migrate with their laptops from home to cafe to client offices.

Glaxo claims it is the first pharmaceutical company to ditch the trappings of traditional corporate culture: the private offices, the hierarchical ordering of space, the one-to-one ratio of desks to employees. By making its environment more social, the company hopes to attract younger, more innovative employees who like working in group spaces.

That, of course, is the mantra expressed by every big company today. The irony is that current wisdom tells us that innovation occurs in dense environments like Center City, yet companies like Glaxo - not to mention Apple and Google - continue to seek wide-open spaces like the Navy Yard. They prefer their density within the confines of their own buildings, rather than on the streets outside.

It's as if they're trying to manufacture what already exists in cities while staying at arm's length from the real thing. Downtowns like Center City are invigorating because they are incubators for serendipitous experiences and encounters that stimulate our imaginations. Those experiences are much more limited in a hermetic office building, no matter how well-executed.

Despite the separation, the new kind of office that Glaxo has built may indeed produce a more creative working environment than the old cubicle farms.

But there is reason to be concerned with this model. No new office building has gone up downtown since the Comcast tower opened in 2008. All the action has been in the Navy Yard. It makes you wonder whether there is a future for the original innovation zone: the traditional downtown.

Contact Inga Saffron at 215-854-2213, or on Twitter @ingasaffron.