How to write regex to extract single words from parentheses?

I have a long string that contains text. I want to extract every word in between parentheses (' '), but only as long as there is no more than one word in between the parentheses (IE, no spaces).

For example, in the below:

<ul>
<li>7-SPEED DOUBLE CLUTCH AUTOMATIC TRANSMISSION (2TC)</li>
<li>MOONLIGHT BLACK SOFT TOP (3YA)</li>
<li>8-WAY PWR FRONT BUCKET SEATS -inc: driver memory, 2-way adjustable headrests, exterior mirror memory (459)</li>
<li>BLACK SAPPHIRE METALLIC (475)</li>
<li>HEATED FRONT SEATS (494)</li>
<li>GLACIER SILVER ALUMINUM TRIM (REQ: ZMP M Sport Pkg) (4MG)</li>
<li>NAVIGATION SYSTEM -inc: hard drive, HD Radio, real-time traffic info, voice command, cupholders (609)</li>
<li> ASSIST W/BLUETOOTH -inc: (4) year subscription (w/609 Navigation System-inc: Online info services) (639)</li>
<li>IPOD & USB ADAPTER (6FL)</li>
<li>M SPORT STEERING WHEEL-MOUNTED SHIFT PADDLES (REQ: ZSP Sport Pkg or ZMP M Sport Pkg & 205 Auto Trans) (7XA)</li>
<li>BLACK, BOSTON LEATHER SEAT TRIM (LWSW)</li>
<li>M SPORT PKG -inc: 18&quot; x 7.5&quot; front & 18&quot; x 8.5&quot; rear double-spoke light alloy wheels (style 261M), P215/40R18 front & 245/35R18 rear performance tires, 8-way manual front sport seats, M sport steering wheel, shadowline exterior trim, increased top speed limiter (w/205 Auto Trans REQ: 7XA Shift Paddles) (ZMP)</li>
<li>PREMIUM PKG -inc: Boston leather seat trim, universal garage door opener, auto-dimming pwr folding exterior mirrors w/memory, auto-dimming rearview mirror w/digital compass, pwr front seats w/pwr lumbar support,  Assist w/(4) year subscription, Bluetooth, illuminated exterior door handles, front/rear reading lights, front footwell illumination, driver/front passenger illuminated vanity mirrors, ambiance interior lighting (ZPP)</li>
<li>VALUE PKG -inc: Boston leather seat tri开发者_高级运维m, iPod and USB adapter (ZVP)</li>
</ul>

I want to get as a result

2TC 3YA 459 475 494 4MG 609 639 6FL 7XA LWSW ZMP ZPP ZVP

What is the best way to parse this? I'm implementing this in C# if it matters

The regex \((\S+)\) should do the trick.

string pattern = @"\((\S+)\)";
MatchCollection matches = Regex.Matches(str, pattern);