CONDENSED CONSOLIDATED BALANCE SHEETS (Parenthetical) - USD ($) $ in Thousands	Mar. 31, 2017	Dec. 31, 2016	[1]
Statement Of Financial Position [Abstract]
Allowance for doubtful accounts	$ 61	$ 73
Common stock, par value	$ 0.001	$ 0.001
Common stock, shares authorized	250,000,000	250,000,000
Common stock, shares issued	173,304,193	172,647,588
Common stock, shares outstanding	173,304,193	172,647,588

[1] December 31, 2016 balances were derived from the audited Consolidated Financial Statements included in the Company’s Annual Report on Form 10-K for the year ended December 31, 2016, filed with the Securities and Exchange Commission (the SEC) on February 27, 2017.