Stock-Based Compensation - Stock Option Activity under All Plans and Other Grants (Detail) (USD $) In Thousands, except Share data, unless otherwise specified	3 Months Ended	9 Months Ended
	Jun. 30, 2012	Dec. 31, 2012
Schedule Of Stock Option Activity [Line Items]
Number of Shares, Outstanding at March 31, 2012	759,577	759,577
Number of Shares, Granted		411,000
Number of Shares, Exercised		(25,415)
Number of Shares, Canceled or expired		(32,001)
Number of Shares, Outstanding at December 31, 2012		1,113,161
Number of Shares, Options exercisable at December 31, 2012		607,159
Number of Shares, Unvested options expected to become exercisable after December 31, 2012		506,002
Number of Shares, Shares available for future option grants at December 31, 2012		641,357
Aggregate Intrinsic Value, Outstanding at March 31, 2012	$ 800	$ 800
Aggregate Intrinsic Value, Granted
Aggregate Intrinsic Value, Exercised		162
Aggregate Intrinsic Value, Canceled or expired
Aggregate Intrinsic Value, Outstanding at December 31, 2012		740
Aggregate Intrinsic Value, Options exercisable at December 31, 2012		625
Aggregate Intrinsic Value, Unvested options expected to become exercisable after December 31, 2012		$ 114
Approximate Remaining Contractual Term, Outstanding at March 31, 2012		7 years
Approximate Remaining Contractual Term, Granted		10 years
Approximate Remaining Contractual Term, Exercised
Approximate Remaining Contractual Term, Canceled or expired
Approximate Remaining Contractual Term, Outstanding at December 31, 2012		7 years
Approximate Remaining Contractual Term, Options exercisable at December 31, 2012		6 years
Approximate Remaining Contractual Term, Unvested options expected to become exercisable after December 31, 2012		9 years
Weighted-Average Exercise Price, Outstanding at March 31, 2012	$ 8.17	$ 8.17
Weighted-Average Exercise Price, Granted	$ 1.86	$ 8.09
Weighted-Average Exercise Price, Exercised		$ 6.39
Weighted-Average Exercise Price, Canceled or expired		$ 8.55
Weighted-Average Exercise Price, Outstanding at December 31, 2012		$ 8.17
Weighted-Average Exercise Price, Options exercisable at December 31, 2012		$ 8.20
Weighted-Average Exercise Price, Unvested options expected to become exercisable after December 31, 2012		$ 8.14