) --

Clinical Data

( CLDA) was the biggest gainer among small-caps Monday afternoon, its shares soaring 55% to $23.30, after U.S. regulators approved its major depressive disorder treatment Viibryd. The biotech company said the drug would be available in U.S. pharmacies by the second quarter. Over 9 million shares changed hands.

Shares of


( GXDX) jumped 26% to $24.83 on heavy volumes after Swiss pharma giant


(NVS) - Get Report

said it was acquiring the diagnostics laboratory for $470 million or $25 per share in an all cash deal.

Rexahn Pharmaceuticals


shot up 20% to $1.57 after Israel-based

Teva Pharmaceuticals

(TEVA) - Get Report

said it had acquired a 6% stake in the company at $1.69 per share.

Several solar stocks were shining on the bourses after Goldman Sachs added

First Solar

(FSLR) - Get Report

to its conviction list. Shares of

LDK Solar


were surging 10.5% to $14.53.

Solarfun Power

( SOLF),

Trina Solar




(SOL) - Get Report

were also up sharply.

Shares of



were recovering Monday after plunging last week, rising 7.2% to $6.23. The stock took a hit last week after it said that

Abbot Laboratories

(ABT) - Get Report

was reluctant to market its pain reliever drug.

Level 3 Communications



Dot Hill Systems



Pluristem Therapeutics

(PSTI) - Get Report


ATP Oil and Gas

( ATPG) were among the other major gainers on Monday.

-- Written by Shanthi Bharatwaj in New York

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Shanthi Bharatwaj


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Disclosure: TheStreet's editorial policy prohibits staff editors and reporters from holding positions in any individual stocks.