Cash and Cash Equivalents - Additional Information (Detail) (USD $) In Millions, unless otherwise specified	3 Months Ended
Mar. 31, 2014 Institution	Dec. 31, 2013
Cash And Cash Equivalents [Abstract]
Financial institutions to held securities	2
Cash and cash equivalents original maturity dates	Three months or less
Bank balances	$ 8.4	$ 11.6

Number of financial institutions in which securities (cash, government securities, mutual funds and money market funds) are held.

No definition available.

Name:	smsi_NumberOfFinancialInstitutionsInWhichSecuritiesHeld
Namespace Prefix:	smsi_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	duration